Grim Tales from Down Below/WMG

Mandy wasn't the traitor that led to the demise of the heroes and Megaville's destruction, it was Mimi.

 * Her fear, her flashback, the fact that her presence alerted a volcanic rock beast and dragged the ragtag group of heroes out of wherever they were hiding, and that Him was on hand to trounce both Raven and Irwin easily. It may be that she's little more than a pawn of Him, but the fear and guilt of betraying others is all on her.

Mimi is the daughter of Stocking Anarchy.

 * Look at this scene and tell me they're NOT related. http://grim.snafu-comics.com/?comic_id=151 Afterall, the last episode of Panty and Stocking with Gaterbelt did reveal
 * Jossed with the reveal in Mimi's flashback showing Raven is her mother.
 * Which itself has been Jossed; Raven is merely one of Mimi's caretakers.

Junior is the biological son -- or technically the ghost of the biological son -- of Mandy and Danny Phantom.

 * Hinted at by the interest that Mandy is expressing in Dark Danny towards the end of the series.
 * Confirmed!
 * Confirmed where?
 * Not really. Its theoretically impossible since he is just recently free.
 * That's Dark Danny from an Alternate Timeline. There should still be a regular Half-Ghost Danny out there somewhere, possibly with a very pissed off Sam.
 * Mandy seems to like the more evil and powerful guys. But if Danny is darker and more powerful...
 * Look at the pictures in bleedman's gallery.
 * Confirmed  in the recently released sequel, Afterbirth.

Junior is the biological son of Mandy and Timmy Turner

 * Kind of crazy but Junior has the same hair and eye colour as Timmy, and his godparents are Anti-Cosmo and Anti-Wanda.
 * Compare the third panel on this page to the the fifth panel on this page
 * Adorkable? Check. Parents that seem indifferent but really do care about him? Check. Having to learn lessons about himself and those around him the really hard way? Just like his old man!
 * Then there's Mandy in the latest comic : "You've got some balls, boy! I'm impressed: I thought you were as spineless as your father."

Junior is the biological son of Mandy and Billy

 * I just doubt he'd pass up the chance to feature this as a plot device. ;)
 * As interesting as that would be, remember that Billy was already dead by the time Grim and Mandy got married.
 * Don't debunk this yet, don't forget, Billy kept coming back. Mandy even kept asking in flashbacks if Billy had escaped again, it's not so impossible. Besides, they reside in the underworld, his soul resides wherever, it's not so unlikely.
 * If that were the case, I'll need brain-bleach since it's doubtful the dead age, and Billy died young.

Junior is the biological son of Grim and some other being

 * There's a reason he appears like Grim but not like Mandy. Also, that would result in Minnie and Junior not being related by blood.
 * If that was the case, then the whole confrontation between Nergal and Grim was pointless.
 * The abortion clinic with a pregnant Mandy were no hints?
 * They're still related by blood whether or not they have different fathers. Mandy's the mother of both of them, isn't she?

Lock, Shock, and Barrel survived the encounter with the Reaperbeast, albeit with mental and emotional scars. Oogie, however, was killed

 * This is going mostly by a karma system. While Lock, Shock, and Barrel did kidnap Junior and bring him to Oogie, they didn't do anything directly to harm him or Minnie and are shown shown to be upset at Minnie's death. Oogie, on the other hand, not only killed Minnie but showed joy at her death.
 * Except that the Reaperbeast was shown... Well, reaping them.
 * Well, it's actually said that it devours the souls, and since it devoured Minnie and Junior's souls, and they were alive, there is still some hope for Boogie's Boys.

At some point in the series, Junior will lose either his demon powers or his reaper powers

 * Clockwork states the the combination of a demon and a reaper should never occur; and the combination is shown to be very dangerous. In order to ensure the safety of the world, someone will do something to cause Junior to loose one of his powers, most likely the demon powers.
 * Exept he didn't get his Nergal powers naturally.
 * No matter how he got the Nergal powers, with them, he's still a Reaper-Demon, and thus, a danger to the worlds. Considering how he got the Nergal powers, they'd be the easiest to get rid of without causing damage to Junior.
 * Invoked in Afterbirth.

Jewel, from the After Birth comic, is an alternate universe daughter of Junior and Mimi

 * Her appearance is similar to a combination of Mimi and Junior's human form. The alternate universe part could explain how Mimi was able to have a child-in the alternate world, she never went through the torture Him put her through.
 * It should be mention that the picture of jewel was done as a request from a fan of there own fan character so she hasnt been confirmed to appear in After Birth and, while its not impossible for her to appear, it dosn't seem very likely at the moment. it should be noted that its possible that bleedman has confirmed her appearing in After Birth and This Troper has simply not found where he did.

Junior is the biological son of Mandy and Nigel

 * C'mon, they look alike. Plus, if the theory that Jewel is the daughter of Junior and Mimi hold true, then, who else would she get the bad enough vision needed for glasses from? Plus, they do kinda look alike... Mandy could have had the mindset that Junior might be better with some Wizard DNA in him...

Junior and Minnie kissed once before/were suppose to before the cool down kiss later on
http://grim.snafu-comics.com/index.php?comic_id=64 Look at the two silhouettes. One shows their mouths and Junior's eyes wincing some. In the one below it, their mouths are gone, the silhouette's heads are closer, his eyes are wide, and part of her wing is covering the point where their mouths would be.

Mandy is putting together some sort of Underworld Fighting Dream-Team

 * So far she's had a kid by the physical embodiment of Death himself, one of the strongest demons in the underworld, and as of one of the latest updates, one of the strongest ghosts in the underworld. Why else would she be so apt to sleep around if not to make a fighting force with power unlike anything the world (or Underworld, as the case may be) has ever seen?

Mimi is one of Mandy's daughters

 * As the above WMG said, maybe she tried to get one from Him. Plus the name. Mimi doesn't sound too far from Mandy or Minnie.
 * Jossed here: http://bleedman.deviantart.com/#/d3e3w7j
 * And here: http://grim.snafu-comics.com/index.php?comic_id=174

Grim Tales is a "What If?" alternate future of PPGD

 * It's the only way to explain how it's parallel to and not in the same continuity as PPGD.

Bubbles is both Mimi's mother and the traitor of Megaville's heroes.

 * With a twist to the latter half of the theory. Yes, there's even less resemblance between her and Mimi than Raven has, but it makes sense when you realize that in the original series Him focused his manipulation tactics on her more than her sisters because she was more emotionally sensitive, thus easier to lead along. Him is smart enough to remember this and not only tricks her into conceiving his child, but taps into her subdued Unstoppable Rage state and plants the idea in her head that the other heroes are "traitors" and a danger to her unborn child, leading to the heroes' destruction. None but her and the ragtag group survive, and she'll be none the wiser about what has happened once the damage is done and Mimi's born, after which Him will release her from his control since he has no further use of Bubbles as a vessel.
 * A smaller indication might be the fondness for creatures that Mimi has with Jeff, a fondness we know Bubbles has in spades, and the fact that she's one of three people that can "kick Him's ass", as Raven so fondly puts it.
 * And in one of the recent panels,
 * Close, but Jossed.
 * There IS an indication that Bubbles is the traitor, though not the mother of Mimi. Here, the conversation between Grim and Mandy hints that one of her 'dumb blonde' friends brought this all upon herself, with Grim commenting that he thought Mandy would be the one to do such a thing. Mandy immediately counters that everyone is capable of doing such things, indirectly discussing the fall of Megaville. So it would seem that a blonde that was friends with Mandy did something horrible that brought doom upon herself and, likely, Megaville. Hmm...

The mother of Mimi will be

 * If the latest chapter are any indications.
 * If you look back a bit further to here, there are a few similarities
 * It may also explain

Blossom is not Mimi's biological mother.

 * Blossom and Dexter likely raised Mimi as their own, but Mimi looks nothing like Blossom. On the other hand, though, look back at PPG Doujin, and you might notice Mimi looks a freaking LOT like Olga, who is growing pretty close to Dexter and Blossom. My guess is that something happened to her involving HIM, likely getting raped and killed after birth, but Blossom managed to rescue her friend's newborn daughter, and so Mimi sees Blossom as her mother.
 * Pretty sure that Mimi's black hair comes from Him.

Grim Tales takes place in an alternate universe from Powerpuff Girls Doujinshi

 * Despite both being written by the same author and having many of the same characters, the sheer amount of differences between the characters seen in PPGD and here simply screams alternate universes. Admittedly, this could be chalked up to character development, but writing such a lighthearted comic as PPGD and then simply sinking it with a Downer Ending Foregone Conclusion seems too dark even for Bleedman.
 * I believe that Bleedman already confirmed that what is shown in that page is an "Alternative Dark Future" to the events of PPGD.