Kaine
popstar Kaine gets into a fatal car accident with his brother. Kaine dies, but the brother lives and is forced to pretend to be the deceased pop singer. extra stories also pop-related but not as dark. the art is really fantastic.
Itou-san (KURAKA Sui)
about a prostitute and an assassin. it had a very "boys next door" (kaori yuki) vibe to it. very dark, very messed up. one of those yaoi that makes you not want to read yaoi anymore. ugh those bonus chapters really tug at the heartstrings
Hellsing
im going to save you a lot of time. "alucard" is "dracula" backwards. protestant vampire knights and catholic regenerators vs. zombie werewolf nazis.
The Long Hair in the Attic
"the bully" might be the most horrifying thing i have ever read and it didnt even have anything supernatural in it :( . "the deserter" is my favorite, and also the creepiest. See: multi generational patterns of abuse
Ludwig Gensoukyoku
they leave their home country "grimm" and travel to "anderson" in search of new fairy tales to meddle in. this was a little more convoluded. the stories are harder to follow. most of this is just a "fashion show" of different outfits the mangaka designs for the characters
Ludwig Revolution