lol alot of these series suggested are rather tame
so i say
Inu Yasha lol he is not only potentially dangerous his total lack of judgment and outright insane friends make him scary

in the begining all he wants is to outshine his brother in ANY way
he likes to kill demons seems happy when he does
the wolfryougathing retard they have as a friend is a dangerous murderer who have killed countless humans but they like him
ASO ASO
i should say that the series change in around vol10-25something to be more family friendly and boring

Hanatsuki Hime - the main guy is a devil which is normally good, but turns berserk towards the end;
Basara - the heroine goes crazy at some point and becames very dangerous, but for a short while;
Goth - I'm not sure about this, since all the characters seem to have a craving for killing and gore stuff all the time;
Tokyo Crazy Paradise - I'm also not sure about the berserk part, but the heroine is very violent, also this is my fav shoujo so give it a try;
B-Eyes - the main character is very dangerous, but the most interesting is his best friend who is totally crazy and kinda evil;

[img]http://img91.imageshack.us/img91/120/zzzkq5.jpg[/img]

I love [color=red]vampires[/color].

I only have these two right now
Ragnarok: It's not that great of a series, but it fits what your looking for.
Painting Warriors: It's ongoing, but right now it seems interesting.

[color=green]"Officially, this machine doesn't exist, you didn't get it from me,
and I don't know you. Make sure it doesn't leave the building."[/color]

Thanks for all the suggestions! 😀 I've only read a few of them.

Does the walker choose the path, or the path the walker?

Until death do us part About a mercenary that everyone questions as being to much a killer to fight for justice, even though he was hired by a group with that in mind. Not complete
Blank Slate In general he is perceived a murder but the opinion changes over time, flashbacks. Completed
Black Lagoon Ordinary salary man joins a bunch of mercenaries, his dark side shown rarely. Not complete
SHINGETSUTAN TSUKIHIME About a teenage high school who after almost dieing sees lines through everything and if cuts along them they fall apart. Complete

I think Akumetsu is what you're looking for

[img]http://i184.photobucket.com/albums/x190/SteelMagnum/MagnumVagabon-sigsmallersize.png[/img]

Biggest Inoue Takehiko fan

KONYA WA TSUKI GA KIREI DESU GA, TORIAEZU SHI NE, only 3 charpters so far but damn its fucking good

Dendrobates Salaryman by day, assassin by night
Akumetsu I don't know if him killing bad people makes him evil but he thinks nothing of killing
Tsumi to Batsu - A Falsified Romance
Kimi no knife
Conductor
Mahou Tsukai Kurohime She doesn't really put on a facade but she's just evil
Shin Angyo Onshi I won't call the protagonist a good person per say
Teppuu
Togari

Chinese Translator Accepting translation requests if the manga interests me!