Black Butler (anime)/WMG

Sebastian does not eat Ciel's soul.
Instead, he forces Ciel into becoming his Battle Butler, and they have even zanier adventures in Hell.
 * I have to tell myself this to stop myself from crying.
 * Maybe confirmed now that the anime is getting a second season.
 * Only about half-confirmed
 * I wonder which one Ciel would prefer, given the choice...

Sebastian, in his true form, is female.
Either that, or a crossdresser. All we know is that he wears a pair of dominatrix boots.
 * Sebastian's true form is HIM?!?!
 * It's not outside the scope of possibilities.
 * Whatever he is is Nightmare Fuel, judging from Ash's reaction and Sebastian's insistance that Ciel shield his eyes.
 * That's anime continuity, though. Sebastian had no problem with appearing in his true form in front of Ciel in the manga. Ciel didn't even seem too fazed by it.
 * Sebastian's true form is an Eldritch Abomination which drives people insane just by looking at it. What we saw was the closest thing a human could see without going crazy.

Sebastian is Malphas from the real demonology
I saw this basic Sebastian = Malphas suggestion elsewhere on the Internet; here is a version with more detail. I shall compare text from the rather terse article from The Other Wiki with how Sebastian has appeared in Black Butler.

He builds houses, high towers and strongholds, - Sebastian has shown the power to restore the Phantomhive manor when it gets wholly or partially destroyed. This is especially apparent as supernatural in the manga chapter 37.

throws down the buildings of the enemies, - The end of the Circus Arc shows him doing that.

can destroy the enemies' desires or thoughts (and/or make them known to the conjurer) and all what they have done, - This one doesn't have much in the way of solid proof, but Sebastian has shown insight into human behavior. However, Sebastian could be based on the Pseudomonarchia Daemonum description of Malphas which differs here from Ars Goetia.

gives good familiars, - Or rather, is a good familiar.

and can bring quickly artificers together from all places of the world. - If you expand the definition of artificers to include all manner of experts, the servants qualify here.

Malphas accepts willingly and kindly any sacrifice offered to him, but then he will deceive the conjurer. - Perhaps this was what happened with the black magic ceremony that led to Ciel getting the contract.

He is depicted as a crow that after a while or under request changes shape into a man, - The beginning of episode 1 of the anime shows this very thing.

and speaks with a hoarse voice. - The black speech bubbles in the manga suggest a voice different from his human one, but his voice in the anime isn't really that hoarse.

Overall, I'd say that's a pretty good fit.


 * I agree with this interpretation. My first impression when watching the Anime was that Sebastian was more than just a regular demon. He is obviously a high ranking one, perhaps at Duke or Prince level (from demonology). The entry for Malphas says that not only does he take a crow/hybrid man-crow form when summoned but that he is a high ranking demon of hell, a "great president" or prince. Also, there is
 * The ghosts from the Tower of London in the anime did say that he looked like a crow in his tailcoat.

Series 2 Sebastian got his new arm from Noah's Arc Circus
He lost an arm in the final episode of the first series, remember? So unless it grew back, this is the only way he could have obtained such an advanced prosthetic.

Ran-Mao is a demon.
When the story Lau tells Ran-Mao is true and he actually is that Zhou he is talking about, then it could be possible that like Ciel he had sold his soul to a devil, just with the twist that he could get a little (super-strong)sister that would do anything for him and follow him everywhere he goes.
 * Sister? You DO realize Lau means something else, right?
 * It would explain her fighting skills. And those cat ear shaped odango could be hiding demon horns.

In episode 17, Sebastian had
That's one of the reasons why he

Trauma, and not any of the things that most real-life Western churches consider "unclean", are the only things that the purification church in the anime considers an impurity.
Mathilda smelled like a demon because she had demon on her, both metaphorically and literally. She was still pretty "pure" or would have been if it and her boss's reaction wasn't traumatic. It's kind of like them getting the Fruit of the Tree of Knowledge of Good and Evil pumped from their stomach, only in this case it's the Fruit of the Tree of Knowledge of Life's Suckiness.

Sebastian's true form is an Eldritch Abomination with Alien Geometries, a Brown Note for Man, who was not meant to know such things.
We only saw flashes of his intermediate stages of transformation in the anime, not bits of the final structure. The feathers are not a direct result of his transformation, but a screen he creates so that the people of London don't get an eyeful of madness if they happen to look up at the wrong time and have particularly good eyesight. Ciel was close enough (both spatially and socially) that Sebastian didn't want to risk him seeing at all, and thus told him to close his eyes.

Sebastian is The Guide, Mk. 2.
With all the raven symbolism, the interpretation that he is meant to be Malphas (a black bird...thing), and the guess directly above (that Sebastian's true form is an Eldritch Abomination with Alien Geometries), this is the logical conclusion.

In episode 17, even if just momentarily, Sebastian was aware of the Fourth Wall.
And when he slammed his hand against the wall, he was really trying create a loud enough noise to get your attention and warn you that you should probably not watch this next part if your mom is anywhere in the immediate area.