 If you liked
Ai-Ren
|
 ...then you might like
Jigoku no Alice
|
There's a lot of obvious similarities here, especially the post apocalyptic world, young MCs and the artificially created humanoid. Alice in hell is Matsumoto Jiro styled messed up, even if this appears to be his take on shounen (it's not though, but the MC is not high on drugs and/insane all the time), so Ai-ren is a bit more sweet and innocent. Both are a treat for "post-ies", so be sure to read them both!