Warning, this Artikel will have spoilers for the Manga of Ao No Exorcist/Blue Exorcist. If Du have not read the most recently released chapters in the Manga and want to avoid spoilers, I suggest Du don't read this article.

Okay, so now, Lewin Light is a very odd and mysterious character. We know where he's from and why he became an exorcist, but we still don't know his backstory, now, do we?
But, after examining the most Kürzlich chapters, I noticed a few things, and sorta tied them together.

At one point, Lewin himself states that he's not like normal people. He told Suguro that ever since he was a kid, he hasn't really felt emotions like normal people do and has trouble feeling anything emotionally. This is our first piece in the theory.
Now, in the most Kürzlich chapter, chapter 86, Lewin and Suguro were searching through an old cloning lab that was abandoned during the Blue Night, but Mephisto kept in tact.
They're going through this lab, and Lewin is Lesen off the name abbreviations on the cloning tubes, speculating that they stand for the names of the demon kings, the Baal. And he's pretty calm through this, as he is through most things. But then they reach one marked "AZ". Lewin stares at it with an almost panicked expression, then he flips through one of the Bücher he has and sees that it's marked as a clone that would be a body for the demon king Azazel. He just goes completely blank while staring at it until Suguro says something to him and asks if he's okay, but Lewin brushes it off and doesn't give an explanation as to why he panicked.

This is what got me thinking.
So, I thought about it for a while and thought he might have something to do with Azazel, but I'm not sure what. Until Mephisto later speaks to him and tells him everything that went down.
So Mephisto teleports them to his mansion and tells them everything. He talks about how they started cloning because the demon king's bodies would rot and need replaced after a while, because mortal bodies can't really contain the power of them very well. Lucifer, the eldest of the demon kings, would have his body give out the most, so he wanted to destroy the world and pretty much reset everything because of it. Mephisto kept him at bucht Von promising to make him a body.
They researched for a while, and Mephisto talks about their cloning methods and whatnot.
During this, he mentions how they started using different, and even Mehr barbaric means to clone, and some of this caused the clones that were created to not develop normal human personalities.

After Lesen this, I stopped and thought for a moment. Lewin's confession to his inability to feel emotion, to him freaking out over the cloning tube, and now Mephisto saying this...
It just all ties in too well, doesn't it?
And not to mention, when Mephisto is discussing this, it shows a person in a cloning tube. Now, at first I just skimmed over it, thinking it was Amaimon's host body, since he mentions how Amaimon's body was the first sucsessful one after they started these means of cloning. But after re-reading, I noticed that that guy in the tube doesn't look like Amaimon. In fact, it surprisingly looks almost exactly like Lewin.

Like, seriously. Look at this.

Clone that looks like Lewin

Also, another thing that I'd like to add about this, is that when Mephisto teleported them to his mansion, Lewin got angry and yelled at Mephisto that they were still researching. Then Mephisto responded with something he generally wouldn't say to a normal human, "It's rare to see Du lose your composure like this. I don't dislike them, those human qualities of yours".
It seems a little odd he'd say this to just an average dude he doesn't know much about, until Du consider, that maybe Mephisto knows that Lewin is a clone.

So, with all this, I'd like to think that Lewin is actually a host body that was created for Azazel, and that he's not really a normal person...

Anyways, that's pretty much it. Sorry if this all just seems really stupid to you, but it really got me thinking and I just wanted to share it with Du guys. :3