Wow Stephen K is kinda right. Both Death Note and Code Geass are awesome animes and there really aren't many animes like it.
But one I do reccomend is "Kigeki". It's a short 10-min anime film, and "Kigeki" means comedy. But trust me, it's no comedy. There's not really any gore in it, but it's pretty dark. It's about a 5-year-old Irish girl who went to ask the mysterious Black Swordsman to kill the English soldiers coming to destroy her village. The swordsman doesn't want to get paid with money, but with books instead. I could tell u more, but it might spoil the story, since it's so short. Despite the fact that it's kinda sad and dark, there are some cute moments. When the swordsman is reading the book, the girl would throw a rock at his head or when she's coming to close, he would kick her (in a cute way).