D.Gray-man/WMG

D Gray Man Epileptic Trees. Beware; horrible unmarked spoilers follow.

Miranda is the Heart

 * Think about it. Not only is Miranda the only one with Innocence that is different from the others, but it controls TIME. Even taking into account the affects of the other innocence none of them can really be said to affect something other than the user/noah/akuma. Miranda's can control time which has no bearing on the Akuma or the Noah. Also, With Allen recently being revealed as a Noah coupled with his 'Destroyer of Time' status along with him having to kill a friend to fully manifest as the 14th... Well it makes sense that Miranda is 'time' there fore the heart. He will destroy 'time' in order to destroy the innocence (and eventually the Akuma) so the war ends. He does want to save everyone after all.

Kanda is a Communist
This is all
 * And now this

is next in line to become a Fallen One

 * From what I've seen in chapter 214 during their meeting, Link advises  to come back to the Black Order or to risk pushing his Innocence too hard and becoming a Noah. Because this is   we're talking about, he doesn't listen and heads straight to the cottage where   is, in hopes of killing.

The Reason behind Akuma Evolution
Is that the final step is becoming a Noah. Each step in the evolutionary line becomes more human. Each step degrades the soul more and more until it completely disappears. The Noahs power comes from dark matter and functions like Akuma's. We never hear anything about any of their parents. Everyone, including the Earl, did not think there was a fourteenth Noah.
 * Skinn was seen to be a normal human before awakening as a Noah.
 * But since the Noah are known for reincarnating in humans, that doesn't rule out that the original Noah (IE the first of each reincarnation line) were hyper-evolved Akuma.

The Earl is...
I personally think the Millennium Earl is a cycle. The exorcist who defeated him last time was twisted by evil, as anyone who defeats the Earl has to become "Bearer of the Akuma". The Earl wears a mask of Akuma. Allen wears a Mask of Mana. That means...
 * So he's basically Sin? This WMG is officially my favorite.
 * Yes, basically. Then, going by this, the Earl was probably an Exorcist who killed the last one, and the strain of encountering and being surrounded by despair likely drove him waaaaaaaay over the edge and into insanity.
 * He says his name is Adam and he's the first Millenium Earl, but he's not exactly a reliable narrator, and crossing the Bishounen Line doesn't necessarily help with that.
 * Actually Mana?
 * Actually Mana?

Cross ISN'T dead
He faked his own death and left the order so that he wouldn't have to watch Allen lose all sense of self when he becomes the 14th.
 * Maria finally came after him like Sadako from "The Ring."
 * The telekinetic Noah tried to assassinate him, but didn't quite kill him despite a lot of blood. Cross used Grave of Maria to turn himself invisible and escape when no one was looking. He is now lurking in the background planning... something.
 * He wasn't wearing his mask when he was shot. The blood is either someone else's, or it's his, taken over a long period of time (a la Fables) and somehow preserved.
 * He can take his mask off and make it into a clone of himself-- the mask is dead for the time being, but he isn't. It would also explain why he hasn't showed up; he's planning in the background while he waits for his mask to regenerate.
 * Even though Mr. Inspector Hitler Moustache stated that Cross's disappearance was the work of Central...hrm...

The 14th will awaken in Allen but because of his and his innocence's will, it will not take over him.
It'll turn into more of a Super-Powered Evil Side.

The person who is the container of "The Heart" is...

 * Go on, don't be shy
 * Aw jeez, I'll start off with the most obvious one then. ALLEN.
 * Well, duh. For starters, it saved Allen's life by patching up the hole in his... heart. And the whole 'Destroyer of Time' shtick. According to the D. Gray-man wiki, the first incarnation of the Earl was killed by the... accomodator of the Heart. Now guess what is Allen's destiny...
 * I think Lavi has the Heart. The author is setting things up to make it look like it's either Allen or Lenalee, but it's going to turn out to be Lavi. That would be pretty ironic, seeing as he's not supposed to be too involved with the Innocence or the war that's going on.
 * That Bookman was shown telling Lavi that if Lavi had the Heart they'd have to leave strikes me as foreshadowing. Considering how things have been set up so that having to leave would be incredibly painful for Lavi (since he's gotten attached to people at the Order despite how he wasn't supposed to) and how the glimpse into his memories during the Ark arc showed how he's beyond sick of war and fighting... yeah, I think Lavi being the Heart is plausible.
 * It has to be Lenalee. If the MacGuffin was named something like "the harbinger" then my guess would be a male character. But "the heart" has to be a girl. Yes, it can attach itself to males and females. But I think it will be genre-savvy enough to choose a girl when it's named so girly. And the other females are just too secondary to be so plot-important.
 * I think it's both Allen's and Lenalee's together. Remember, everyone was confounded when it turned out that Allen's arm hadn't been obliterated by Tyki Mikk, and the fact his Innocence had saved him. Yet Lenalee's Innocence did that same thing. Allen's and Lenalee's Innonence combined form the heart, and to destroy one is impossible while the other survives; this would fit, since it's unlikely that the "great heart of the Innocence" would have the exact same properties as the other Innocence, it would make destroying the Heart so much harder, and it would also round off the number of Innocence into a neat 108, counting the two Hearts as one. Of course, two Hearts as one also makes the romance sweeter, since Innocence are attracted to compatible users and all that.
 * That's... a very, very good theory. Now that you mention it, it seems obvious. It would be a twist, it would be romantic and explain a lot.
 * Another possibility that can add to the romance is even if it is just Lenalee, with Allen being a Noah (or mostly there), and her being the heart, you get a really interesting variation of Romeo and Juliet going on. Just a thought.
 * Sorry everyone, I must disagree. I don't think that the Heart Innocence even exists. Seriously, God isn't that stupid. He wouldn't make this weapon to defeat all evil and then give it a Self-Destruct Mechanism just in case a Big Bad figures out that it's the way to destroy humanity's one last choice. Let's give the Big Man some credit here.
 * That's probably the best theory. Tyki already proved that Allen isn't the heart. And just cause Lenalee's innocence protected her, doesn't mean she's the heart- Chaoji's did, too. It could be just some hype or rumor the Order jumped on that the Earl spread.
 * Sokalo. No exceptions.
 * Timcampy?
 * I once heard a great idea in fanfic: Hebraska. She's technically an exorcist as "Innocence did that to her," and she 'holds' waiting Innocence.
 * That makes sense why she's completely enveloped by it and it's constantly activated.
 * Didn't it say that she's the holder of the Innocence Cube, which is what made her like she is, unaging and able to judge all the factors about Innocence and an Apostle, like Synchronization Rating and such? I could've sworn when they show up and give a dead Apostle's Innocence to her it states that.
 * I think it's Timothy. I mean, sure Allen and Lenalee's Innocence saved them and sure Allen's has a mind of its own but Timothy's can TALK to him AND has a mind of it own! It also has a different accent apparently, meaning that its not French like Timothy.
 * It's contained in Kanda. It's not Mugen, but it is his literal heart.
 * Miranda Lot, she's the only one who's Innocence has no offensive ability what so ever. Look at it this way, if the Heart is self aware like the Earl claimed, and all of the other Innocence dies with it, the Heart is going to do everything it can to keep the person that can synchronize with it away from the front lines. How does it do that? Not let the person use any offensive abilities.
 * No one. The Heart is Kingdom Hearts.
 * Bookman, by virtue of being the least likely Innocence-using person to be the Heart. At least if this is that kind of story.
 * Since Hoshino likes to mindfuck her fans with wacky plot twists and reveals, I'd say Johnny has it. I mean, he's weak, he's not exorcist, for a side character he's had his screentime, Earl doesn't even know he exists and since everyone thinks the container must be very powerful, nobody would suspect a thing...
 * Hmmm...that would explain why he has so much screen time.
 * Allen. Mostly because of apocryphos, It has said that the heart is worried about Allen, and that it's trying to protect him. Given that Apocryphos is probably the strongest character loosely aligned with good, being absorbed by apocryphos is probably the safest thing for the heart. That said, its still a terrible idea and allen should kill him.

In the future, Lero shall become Hagrid's umbrella
If a wizard can cast spells using broken pieces of a wand, why would the Ministry have allowed him to keep the pieces to graft into an umbrella? We haven't seen the umbrella fly or talk, but Lero could just be lying low until the appropriate time.
 * That could also mean that Hagrid is the Millennium Earl in disguise.
 * You have just ruined my Harry Potter experience. Thank you so much.
 * This troper, who is responsible for the above Epileptic Tree, gives a bow. She is oddly flattered by the discovery that she is something similar to a Paranoia Fuel Station Attendant. Incidentally, her enjoyment of Harry Potter has greatly increased since coming up with this theory. This may or may not have something to do with the fact that she is aligned firmly on the Earl's side.
 * Does that make Timcampy the Golden Snitch?

The Millennium Earl is related to Santa Claus.
Well, they're both approximately the same size, and they both fly through the night delivering gifts, after a fashion. What is seeing a deceased loved one one last time if not a gift? And then the souls are all wrapped up nicely. Eliade in particular got nice "wrapping paper".
 * Why, God, why?
 * Once again, this troper is strangely flattered to basically be called a Paranoia Fuel Station Attendant and a Nightmare Fuel Station Attendant.
 * As frightening as that thought is, it makes me smile to think of the children on the naughty list being turned into akuma if they misbehave...

Allen will turn against the Order
Because he's the only person in the entire world who has the potential to see both the Innocence and the Noah's for what they really are. It will turn out that it doesn't matter which side is the victor, humanity is screwed either way, and the only way to stop it is to put an end to both sides. The "other side" of the war is humankind. Once the Innocence's Heart is destroyed and the Earl is killed, the war is over.
 * Given that, it could very well be the case...

Timcanpy is going to come out as the real villain in the series
Cross created Timcanpy, Cross  therefore   has some connection to Timcanpy, and even goes so far as to say that. Because of that, it is entirely Timcanpy's fault that  because Timcanpy chose Allen! Not only that, but doesn't it seem like every time Timcanpy is on someone's head, he is probably eating their brains.

The Innocence are created from Akuto.
Akuto is vital to a place sometimes described as Heaven, and is a 'reflection of the spirit'. The Great Flood was caused by the final battle to separate the Upper and Lower Worlds, and the Innocence are Heavenly Magitek that were left behind. The Great Heart of Innocence generates more Akuto (and therefore powers the other 107 Innocence), so if the Earl destroys it, then the Akuto is gone and everyone will be killed.

By this logic, the Great Heart of Innocence belongs to Yumemi.

Cyril and Tyki have different Fathers
Or else different Mothers, with Tyki been an illegitimate child. It would explain them having different last names despite been brothers.
 * Logical, considering the fact that Cyril seems to have had a pretty nice life, whereas Tyki was making a living by coal mining, not exactly the high life.
 * Who said they're biological brothers at all? All of the Noah refer to themselves as siblings. They don't have to have any blood relation.

Cross is this dimension's Clow Reed
There's a bunch of evidence for this theory, first being that Timcanpy is a magical gollum, just like the Mokonas from ×××HOLiC and Tsubasa Reservoir Chronicle, even with the same ability to eat things for storage. Next, the school that the kids in HoLic go to is named Cross Academy, an obvious shout-out to Clow's other world counter part. Both are magicians with long hair and the ability to manipulate life and death to an extent, (Clow with and Cross with Maria) and they both have beautiful long hair. This also plays into the fact that...
 * Well, thanks for making the manga even more complicated than before.
 * Allen is thus that dimension's bleached haired Syaoran. Lenalee is Sakura, and their parents are their reincarnated clones.

Cross isn't dead, he just went to a different dimension
Cross was able to create a dimension traveling golem like Mokona and decided that rather staying for the impending doom of their world, he'd move onto the next.

65 has become a Noah.
Okay, so everyone's favorite... Thingie seems to have not been present in the more recent chapters. Why, you ask? It's easy. It's because he told Komui that he went on vacation a while back and didn't come back. Komui, being the somewhat Cloudcuckoolander like, merely assumed that he was eaten by badgers, or something. But the truth was that he had a Face Heel Turn and became the Noah that doesn't look human, Mightra.
 * Instead, I think he was eaten by badges.
 * ...I meant badgers, but that's actually funnier.

Allen being the "Destroyer of Time" isn't a good thing.
Everyone in the Order seems convinced that it means that he'll defeat the Earl and save the world. In reality, it means he'll become the Earl, probably inheriting the position after he manages to defeat the current Earl. Then he'll turn evil and kill everyone. The Order'll feel pretty silly.
 * Yeah, why has no one in Canon pointed that out yet? Or better yet, the possibility that Allen will just wipe out all of humanity and literally "destroy time"? These were the first things running through this troper's head when she first encountered that prophecy. It's always bugged me.
 * I don't think so. Remember, D.Gray-Man has had its darker moments, but it's still clearly on the idealistic side of the scale. This just isn't the sort of story that would take such a dark turn, unless it would be Allen being told that this was the case, and him pulling a Screw Destiny by saving the world (and then somehow following the prophecy anyway.)

Bak Chan will kill Alma.
It'd be retribution for killing. The kid's last name is Karma, so it's pretty fitting. What goes around comes around...

Lenalee and Allen's Innocence was originally one complete Innocence and possibly the Heart.
The original innocence was suppose to be a full-body armor. Allen's innocence makes up the upper body and Lenalee's Innocence makes up the lower body. This would also explain how two different Innocence manage to have a similar level of sentience.
 * This troper thinks that this will make absolute sense, as you see... Allen's innocence was originally Parasite, and Lenalee's one Equipment; The two main innocence types. Throw in the fact that they both were  Further coupled with the fact above that Allen's one was the arm and Lenalee's one the legs, it pretty much seals the deal. Come on, even  This troper is completely convinced at this WMG.
 * This troper doesn't mind 'Lenalee's Innocence + Allen's Innocence = the Heart' theory, but thinks it needs a better argument to support it than that. How do you define a 'similar level of sentience'? All Innocence is sentient and not only Lenalee's and Allen's came to their help - see Chaoji, for example - or seemed to have reached an understanding with them. And most of the parasitic type users had their Innocence "stored" in the upper half of the body (Suman's right arm, Krory's teeth, Maria's vocal cords, Timothy's forehead), so Allen's arm can't exactly be an unique representation of it unless his Innocence speards out and actually covers it.

Kanda is Allen's father.
That woman who Kanda keeps having flashbacks to looks a crap ton like Allen. The guy who Kanda  was probably lovers with that woman so that would mean that Allen is her son and Kanda is the father. That would explain why Kanda hates Allen so much;.
 * I doubt it, because Allen was abandoned by his parents for his weird arm. If Kanda was his father, then he would have recognized that Allen was an accomodater. Though he could have abandoned Allen because he didn't want him to be an exorcist...

The Millennium Earl is actually Mana
In Chapter, The earl said that he wanted. To add more, the earl's human form looks almost exactly like Mana. And here's Mana with a hat that look's like one of the Earl's.
 * And then how would've he watched Allen call Mana's soul into that akuma shell and the transformation into an Akuma?! I think it's impossible... then again, maybe the Earl is Voldemort, and somehow managed to split his soul and made a horcrux out of Mana.
 * Proven, yeah? 14th said Earl was "brother" during their lovely encounter in chapter 189,and everyone's been saying that the 14th was Mana's brother since the Ark Arc.
 * Which doesn't prove anything. Everyone knows that Noahs see each other as siblings, addressing to each other as "brother". Besides, the 14th was running from the Earl with Mana, his brother. Also, I don't see the event in which Allen was turning Mana into an akuma as possible if Mana was the Earl, because the Earl was there the whole time. So no, not proven~

In the future Lavi will become Rufus Barma.
Red hair, fetish for knowledge, dashing good looks... All he needs is to steal someone's eye and he's set.
 * Dear God, I love you so much right now. That's genius!

Allen is Usui Takumi's ancestor.
In chapter 52 of Kaichou wa Maid-sama! it is revealed that Usui's. We also know that Usui is part English. Allen being Usui's grandfather explains Usui's bishouen looks and his Chick Magnet status.

The reason why DGM exists is because Lavi wrote the whole story down.
Lavi is a Bookman apprentice, right? And Bookmen are supposed to record history. So, after the whole story of DGM was over, and Lavi became a full Bookman at the end, the first thing he did was to write down the full story of Allen Walker. He could have asked witnesses who were there for scenes he didn't see.

Innocence is made from murdered angels
The "default" form common to all Innocences appears to be a headless and limbless angel torso. This is also the form Suman's Innocence took when he Fell. My theory is that the Innocences were all originally angels that the pre-Flood humans turned into anti-akuma weapons to fight against the Earl. This involved chopping off the angels' heads and limbs to make them more manageable, but since angels are truly immortal, their power and even something of their mind lives on.
 * This troper agrees to a point that Innocence is somehow connected to angels, given the angelic symbolism, and the fact that in the actual Noah story in Literature/qTheBible angels were said to have come down to earth during that time, but doesn't think they were murdered.

The Millennium Earl created modern humans in order to harvest them for power
Since Dark Matter is made from the Millennium Earl's soul and he is able to draw it back when he wants, whenever a demon levels up, this also increases the Millennium Earl's distributed power pool. Killing every human on Earth would strengthen the demons immensely, and after that the Millennium Earl can just order the demons to self-destruct in order to draw back the evolved pieces of his soul. At this point, he might be powerful enough to defeat God. When the Millennium Earl created the modern humans, he was planning exactly this, but he had to wait seven thousand years for the humans to fill the earth with the power of exponential growth and provide a good harvest.

Mad science will win the day
The Millennium Earl will succeed in destroying the Heart, but thanks to the science team all will not be over. It turns out that the Millennium Earl is not immune to things like Komuvitamin D. An assortment of various chemicals delivered by the latest Komurin robot will turn the Millennium Earl into a Harmless Villain with bunny ears.

Everything happens inside a computer
Ever think it's strange how the Ark can be downloaded as if were a program? That's because everything in the story happens inside a computer simulation. Abilities that seem supernatural are really nothing more than the equivalent of cheat codes to the simulated physics.

Kanda is the new Noah of Wrath
Now that Skin Bolic is dead, the Noah of Wrath is due for a reincarnation. My guess is that Kanda will be the one to awaken as him. The mechanism of Noah selection is unknown, but Kanda killed Skin, was the only one close by when he died, and, perhaps most importantly, has a naturally short temper and a preference for solving things with violence. It could be interesting to see if Kanda manages to hold onto his technical fighting style under pressure from his Noah memories and if Kanda's meditation experience helps keep him focused.
 * Although still plausible, highly unlikely with Kanda actually being a test tube baby now.

One of the Walker brothers is Allen's real father
I can't believe this isn't here yet! Well either Mana or Neah is Allen's father.

Cross is actually Lavi from future
Oh come one,how did we miss it?. Look at them, they both wear eyepatches, like to flirt with women, tease people, don't give a damn about rules and have long red hair. Also, with Lavi being future bookman, I think he could gain the knowledge about the magic Cross is using. My theory is that since his hammer still haven't been repaired, he will pick up Cross' revolver innocence. This may be the reason of Cross sudden disappearance, he knew it will come and had to leave it. Then at some point in future he will discover a spell able to return to past (Or maybe Miranda's Innocence will be able to do that). Either way this or...
 * Can't happen. Lavi gets his hammer back. As seen here

Cross is Lavi's father
They look and act waaaaaaaaay to similar.
 * They do have alot of things in common, and we all know Cross is a Casanova, and likes him some fine wine and some fine women, so it wouldn't be suprised if he fathered a child.
 * It's impossible for them to be father and son, because Cross has blood type AB and Lavi has blood type O.
 * O is dominant. You can be blood type O and have a recessive A of B from the other parent.
 * Not true. O is recessive. A and B are codominant, but O is recessive. This troper has type A blood, with a type O mother and type A father.

Cross is Allen's Father
It does make sense in the long run, Cross and his mother probably knew Allen  and sent him to be adopted twice. Earl killed Allen's mom, and Cross spent years improving himself in order to protect him. Then when Allen was about to left to die, he comes to train him, but had to keep the connection a secret. Hence, his Jerkass behavior with Allen, although recently it's starting to resurface.
 * Does make sense, seeing that Allen doesn't remember what his "real" parents looked like.
 * This one is impossible, for the same reason the Cross as Lavi's father theory is. Cross has type AB blood, and Allen has type O. Type AB parents cannot have type O children.
 * As noted above, a pair of AB parents can't, but all type O blood requires is one parent with type O. If the mum was type O, either homozygous or heterozygous with a recessive B or A, then the offspring of an AB man could come out O.
 * To continue the lesson: if Mummy was type O and had OA genes and Daddy Cross had AB, then the possible types for the kids would be A, AB, and O. If she was OB then they could be B, AB, or O, but not A. If she was OO, then the kid would be type-O, but would have a recessive A or B from Daddy, and thus unlike Mummy could have non-O kids with the right partner.
 * This is not sex-linked, so it works the same if you reverse genders.
 * This is pretty much all irrelevant as O is recessive. To have blood type O, both parents would have to donate an O allele. As Cross has AB, he does not have an O allele to donate, and therefore cannot be Allen's father. Look here for more extensive information about blood types.

Lavi's Right Eye
...Is a Sharingan.Thats how he's able to record what's happening, and also how he was able to find the real key in the midst of the hundreds of fake ones,since the Sharingan automatically gives the user a Photographic Memory and Hyper Awareness. He keeps it covered because he can't deactivate it.
 * Disregarding the obvious Shout-Out, this theory actually holds some water. Here's the link for that particular moment in the Ark arc (lol, Ark arc). Clearly his right eye is not normal.
 * He could have also given up the eye to gain those powers

The Akuma's evolutionary process...
Is an attempt to create the perfect being. As the Akuma kill, they slowly evolve into more powerful forms. So far, that evolution has led to the Akuma Level 4, which appears like a corrupt form of a Seraph, yet they are also more powerful than any singlular Noah, barring the Earl. From what we've seen on the attack on, there are as many Level 4 Akuma as there are Noah. From the Earl's implications, there is a level farther above even the Level 4 Akuma, which would be a level 5. An Akuma more powerful than the Level 4 is a scary, and inconceivable thought, considering how much more power a single Level 4 has in comparison to Exorcist Generals and Noah, barring the Earl himself.

Still, taking this into account, a level 5 would probably look just like a normal human being, and the final step in the Akuma's evolution. This must have been what the Earl intended all along: the creation of a being beyond any other in existence. If it's even possible, the Earl would probably transfer his own conscience into this new body, casting aside his now-inferior Noah form. If that is his goal, he's probably aiming to kill God.
 * What if the Cardinal in Chapter 202 is actually a Level 5 Akuma. I mean Allen was turning into the 14th so maybe that’s why his pentacle didn’t go off. Plus the cardinal had a creepy hand, a weird aura and he knocked out/killed? the guards.
 * No, the Cardinal is an "Apocryphos", a sentient Innocence whose sole purpose is to protect "The Heart". A level 5 Akuma would be similar to, but a step even higher, above the kind of Akuma Alma Karma became. He's technically a Level 4.5 Akuma, who has the unusual ability to also wield Innocence. That leaves me two options as to how an Akuma can evolve into a Level 4 and beyond. One - they are the soul of a former Exorcist turned into an Akuma, or... Two - a person who volunteered themselves to become Akuma, instead of the forced, resurrected souls the Earl commonly uses.

Either Neah or Mana is Tyki's father
The fact that Tyki looks near-identical to Neah is easily explained if he's actually a Walker.
 * I Kind of just said this but I agree with you about Mana or Neah...If it was Neah then that would make sense why he resides in Allen.

Where all the redheads at?
Above, my fellow Tropers have posited the followng: 1) Cross is not dead, and 2) Lavi and Cross may be related. Also, both have disappeared in recent chapters-- and really, would Hoshino mention specifically that Lavi has gone missing if it didn't matter? Well, what if Cross went to find his son/past self/illegitimate child and the two now lie in wait to ?

The owner of the Heart is Sora
It's his keyblade.

Lavi is a pyromaniac.
Just how many freaking times has he used Hellfire Cyclone?

The Earl was originally sent to “test” humanity and simply went insane over time
Let’s put it like this: you do something long enough, you can end up forgetting your reason for doing it in the first place. Think about, the Earl’s apparently been in this whole making Akuma business for several millennia, who’s to say that he didn’t have a different purpose for creating Akuma and just lost sight of it over the years? The theory comes from how the Earl’s essentially Satan in the D.Gray-man universe and in the Hebrew Bible Satan was “The Prosecutor,” who had the job of tempting humans and reporting back to God about any who gave in. Now, what does the Earl do but tempt humans to break the cycle of life itself and try to bring back the dead? The Earl himself says early on in the series that he makes Akuma for the peoples own sake.

The existence of Innocence would then be justified as basically the reins under which the resulting Akuma are kept. Akuma may “symbolize human suffering” but letting them run loose would be stupid given the high levels of destruction they cause. However the Earl considers them his “children,” and watching them be destroyed by these humans who constantly gave into despair century after century drove him over the edge. Hell, the Fourteenth straight out says that the Earl's going mad.

Lenalee's Crystal-type Innocence is...
The form of Innocence closest to the Apocryphos, the "Sentient Innocence". It makes sense when thought about in context. The Apocryphos can take on Human form, and the Crystal-type Innocence is made of the Exorcist's own blood infused with Innocence, or even scarier, the Innocence replaces the Exorcist's blood entirely. But even with this, the Parasitic-type Innocence is as similarly as close to the Apocryphos, as it is literally born as part of the Exorcist's body, if Allen is any indication.

The Heart has significance, but not in the way the Order or the Noah think.
I think that the Heart is not the Innocence that keeps all other Innocence fragments going but rather is like a most central fragment that can recreate other fragments of Innocence. If you really need all 108...109 pieces of innocence to defeat the Noah, then the Order is pretty much screwed, with about 10+ fragments already gone. The Heart isn't a power source nor the main and most powerful Innocence shard left, but rather the only fragment that can regenerate other Innocence fragments. The Heart exhibits this regenerating power in the way (and c'mon lets face it here, its obvious) Allen heart (symbolism!) and Lenalee's legs (yup her too) were regenerated. The Earl sees this as a threat 'cause if the Heart keeps bringing into existence new fragments of Innocence, the war will never end. The only reason why no new fragments of Innocence haven't yet been discovered is because the Heart is currently dormant, its normal powers and its active user(s) suppressing its special capabilities. The rumour of all other Innocence fragments going *Boom* if the Heart goes *Boom* is a ploy by the Earl. If the Order discovers the Heart, they would do whatever it takes to keep it (and its exorcist) away from the front lines (and thus the risk of going *Boom*). The regenerative capabilities of the Heart are only activated in times is grave and extreme peril.

Leverrier is....

 * Actually Hitler. Or the fictional blonde counterpart of him at least. I mean, look at him! And with the attitude of self-righteousness and arrogance, this guy has all the making of Hitler.
 * He's got the 'stache!

The Earl isn't 'immortal', but can possess others.
It's been mentioned that The Earl doesn't re-incarnate, but the existence of his human form might suggest that he's switched bodies as the need has arisen. When Wisely joins the Noah, the Earl mentions that only the two of them retain the full Noah identity, which could be interpreted as meaning that he (The Earl) has changed in the past. This is partially inspired as an explanation to the 'Mana as the Earl' theory(ies) above; The Earl letting Allen live, and his mixed feelings about the 14th, might be a little bit more interesting if this idea's right.

As for how Mana was used in an Akuma creation ritual... Maybe The Earl's possession kills off the victim? Though it could merely displace the soul, or perhaps The Earl always uses the soul of his new body to create an Akuma.

If this is true though, it makes the 14th's desire to 'become the Millenium Earl' a little bit more complex.

Timothy's Innocence is an Apocryphos.

 * The Apocryphos is known as the "Sentient Innocence," and Timothy's Innocence can think for itself and can communicate with him.

End of the Noah Clan?

 * Because of the way Japanese grammar works, can be read a couple of different ways in English. One is  As to who or what might've appointed him as such...well, that's a theory for another day.

The Noah serve the Old Testament's God

 * On their first encounter Road says to Allen that the Exorcists serve an "Impostor God" and that they, the Noah, are the apostles of the "Authentic God". And also that God wished to erase humanity and had given the Akuma to the Earl for that purpose. Thus the war between the Noah and the Order may be one between the vengeful God of the Old Testament and the New Testament's loving God, each providing their own weapons to their apostles. Although one might question why the former hasn't won yet considering its overwhelming superiority in firepower (it's lampshaded in the manga too)…

NONE of the Exorcists have the actual heart.
The Heart either belongs to someone we haven't seen or someone that we've seen that isn't an exorcist. Or it's completely independent. The reason Lenalee's and Allen's innocenses have been so "special" is because they contain "pieces" of the heart. Why do I think this? Apocryphos said that the Heart wanted to meet Allen. If the heart belonged to someone that was already close to Allen, then why would it want that? Wouldn't it be easier to just influence its host and get it to go to him?
 * Plus, the Earl is certain that the bearer of the Heart is already awakened and fully conscious but hiding his true nature. So that would be weird to learn he's one of the exorcists, considering we already know all of them. Apart from Cross (who is no longer an Accomodate according to Hevlaska and may very well be already dead) there is no-one suspicious enough to have this role among them...

All Innocene will evolve into parasite types in the end
First Lenalee's and now Kanda's Innocence developped into a crystal-type Innocence. And it's been stated in-manga that the crystal types aere somewhere in-between equipment and parasite type Innocence. So my guess is that an equipment type Innocence that is powerful enough will evolve into a crystal type one after the user had a near death experience (or runs out of healing power, in Kanda's case) but survives it somehow. Should the same thing happen again, it will then evolve into a parasite type. It's also stated that parasite type Innocence are stronger than equipment type, so they might evolve to make sure their user doesn't have another almost run-in with death.

Humanity is best off if both the Noah and the Innocence destroy each other.
While the 'win' condition of the Noah seems to be "Destroy the Heart," the 'win' condition for the Innocence would be to "Destroy the Noah." Given the current evidence, it is reasonable to think that the only way for it to do that is to prevent the Noah from reincarnation/reawakening. Even if that isn't true, this seems likely to be the easiest & most certain method for it...and given that all of humanity are candidates...

Innocence isn't God.
It's just WMG on the part of those who found it.

Road will eventually switch sides...kind of
Her Villainous Crush on Allen has already led her to willingly help him at least twice, and if the Noah succeed in their plan to DESTROY HUMANITY, Allen will inevitably die. Road will eventually decide that if she switches sides she will have the best of both worlds; she'll get to keep killing and Allen will get to keep living. That said, she will still be the same Road just siding with the good guys. On the Sliding Scale of Anti-Heroes she will most likely end up as either a Type IV or a Type V. With the way things have been going, there's still some credibility for this provided that Road isn't. Tyki seems like he could end up turning as well.

Lavi's covered eye is 'all-seeing'.
If you look at this link, it's obvious that something's up with Lavi's eye. Whatever it is, it seems useful, but that wouldn't explain why he covers it. And so the theory is revealed...his eye takes in everything at once. Since it overrides his senses (and is most likely a lot for his brain to handle) he doesn't use it all the time. It could cause him to pass out, or to get a migraine of the likes the world has never seen...

Kanda has lost his regenerative power
Almost dying has to have struck quite a blow. more specifically, Kanda complains about getting a hangover. This comes as no surprise considering he and Johnny have been running from bar to bar. but he specifically states he has never had a hangover before.

Will Allen be immortal by the end
Allen is the 'Destroyer of Time'. Does that mean he remains under this title until they find the Heart. Or implied earlier if he does kill the Earl he turns into the Earl. If he is the Heart then does that make him stay alive until all the Noah, Akuma, and the Earl are dead forever. Allen also has the 14th in him, that technically makes him part Noah, even if he does not want to be one. It seems as if they never die except for killed by an exorcist.

Allen and Neah are actually two sides of the same coin i.e. they're were both originally Neah Walker
In chapter 187 Wisely said that he was the only Noah (discounting the still alive Millenium Earl) who, due to his ability to see into minds, accepted his Noah's memories when they came to him and thus his Noah identity, whereas the other Noah remained in control of their human identity.

In chapter 117 Allen Walker slashed directly at "the Noah inside Tyki Mikk" thereby leaving "the human Tyki Mikk alive". As such, had he succeeded, Tiky Mikk could've continued to live a normal life as a human, as a human named Tiky Mikk. After this, Tiky Mikk transformed into his "true Noah" where his (i.e. Tikky Mikk's) personality was completely suppressed. My theory is that it's the same situation with Allen and Neah, with a slight difference. Neah was said to be a "new" Noah, who didn't fit into the traditional reincarnation cycle. Because of this I assumed that Neah's personality is in fact the original Noah memory of the fourteenth Noah (with him being the first fourteenth, his memory would be the original imprint).

I've theorized that initially, Neah Walker became 'the fourteenth Noah named Neah', and that Allen Walker is an amnesiac 'human Neah' due to 'Noah Neah' dying (being reincarnated as Allen with 'Human Neah's' personality before Neah became a Noah, albeit without any memories).

However 'Noah Neah' still existed in the form of the Noah memory and since Neah's body was still alive, it tried to retake control of it as he awoke (which was probably due to Allen's hardships & encounters with other Noah while working for the order). Instead of Allen recovering memories of his time spent as the human Neah Walker, Neah continues to live on in the form of his Noah memory.

Following this theory, Allen and Neah Walker share the same body more as a split personality, rather then a human host serving as the reincarnation for the past Noah, as is the case for the other Noah's. 'Noah Neah' simply never left while still keeping his memories attached to him, leaving Allen to build up his own persona without 'Noah Neah's' influence.