I suggest for you a sad korean manhwa isShin Angyo Onshi and you can check my amv of this manhwa which turned to anime movie only about the first 2 chapts ^^
its starts bad.. guy, 16 years old.... serial killer......... stuck in hell for 300 years (poor him)
the demons dont want him anymore and dump him on earth... with some curses... if he tries to commit a sin or tinks about killing his neck starts to bleed.... if he keeps it up his head will fall of and if that aint enough he only got 108 days to gather 108 toga's (sins and crimes manifested in a sort off spirit) if he hurts a human while doing this he'll feel the same pain.. and to gather these toga's he has a sword named togari that gets it strength from how evil its wielder is, but togari also eats evil souls.. so in fact its a death punishment..
and the world changes a lot in 300 years..
and even if he completes his task.. he wont be able to stay on earth but will go to heaven to be reborn........... to bad he is falling in love (a hardnoticble love, but if you pay attention there is)
he is so evil^^ and if you see flashbacks of his youth aaah! how tragicly and full of pain...........
read it and people if you got perhaps now a manga where the main guy is kidnapped in the past and doesnt remember it but has nightmares and get kidnapped again
give me the title.. this plot looks so hot^^ i wanna read it