Alright, so I'm looking for a character that because of some reason (cursed armor, evil power within, ect) he goes crazy. Not just regular crazy, but bloodlust crazy. 🙂 And he gets super strong/powerful while he's at it. OH! Also, the main character can't be aware of what he's doing; I want him to either black out, or to be trapped somewhere in his own subconscious.

Examples! Bleach (When he turns into the long haired hollow thing), Berserk (when he puts on the berserker armor), 666 Satan (When Satan comes out), and Naruto (When he loses control).

Anyway, please and thank you!

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

These are not exactly what you are looking for because the characters are not unaware of what happens to them, but maybe you'll find something you'll like...
Ao no Futsumashi (I see you are already reading it)
Dawn - Tsumetai te
Dogs and Dogs: bullets & Carnage (I mean Badou, when he runs out of cigarettes 🙂 )
Rurouni Kenshin
Samurai Deeper Kyo

And probably Hakkai from Saiyuki - but it's not very important to the plot.

hmm... maybe Inuyasha
he is a half demon and there are times when his demon blood takes over and he goes into a survival mode killing frenzy (but thats a little bit further on the story)

Elite Yankee Saburou thou the manga isn't scanlated :'(

"Sanity is for the weak"

Dorohedoro fits (though doesnt show on the first few volumes).
Chronicles of the Cursed Sword (read it quite a while ago, but im pretty sure it does have something of sort).
Get Backers (Ginji when turned into Thunder Lord)
And Shingetsutan Tsukihime not rly what u wanted but i think u shud also check it out. Its rly good x). 😀

1-2-3-4-5-6-7-8-9-0!

O-T-T-F-F-S-S-E-N-Z!

I second some of the above mentioned stuff and I'll add Hellsing (most of the characters are bloodcrazed so they won't count, but the main heroine - one of the few more normal characters - goes completely insane at some point later on... 🙂
Soul Eater got something like that too.
Rosario to Vampire as well (been a while since I've read that one though)

Lunar Legend Tsukihime
It happens in the beginning, but I'm not sure if it happens throughout the series, too, although I think it does. 😕

Ichiban Ushiro no Daimaou

Main character's power is released later in the story. Probably exactly what you want.

The Battle of Genryu: Origin
This hasn't been scanned but 2 of 3 volumes are out by CMX. You'll understand on the first page.

123 Change

When you meet Zero, you'll understand, although she appears after a while into the series.

Pumpkin Scissors
He goes into more of a trance, but isn't blood thirsty. Not what you asked for, but might interest you.

Hero Tales
I think it only happens in the first chapter, so you might want to skip this.

I know another/others, but I forget what they are... 🙁

I care waaaaay too much... 🙁

[img]http://img121.imageshack.us/img121/6540/picsmaller.png[/img]

En Passant

When the black rook gets bored, he transforms into some killing machine. If the craving is REALLY strong, then he'll become a real beast. If it's just mild, he'll know what he's doing. [Chapter 3, Chapter 8]

Have you tried "Higurashi no koro ni >insert next part<"
The girls in there are just serial killers.

I've read some of these, but not most of them. Thanks! 🙂

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

Kekkaishi fits when the main char goes berserk twice or tree times in the manga... but thats nothing mayor and he gets over it pretty fast