I think it's so hard to pick just one character....but if I had to tell who was high on the list, I would definitely say Kurogane from Tsubasa.
|He's like, half-ninja, half-samurai.|
Kurogane is an interesting character. He's a classic antihero, coming across tough at first but later showing a soft side.
He doesn't really get deserving of "favorite character" status until volume 13, however. That's the backstory volume. Excuse me while I choke back tears, remembering the one time I read it. Basically, young Kurogane is the son a legendary monster hunter who protects their town. But when a horde of monsters come after the town, aforementioned father doesn't hack it. Kurogane takes up his father's mantle in a fit of rage and rips apart all the monsters like the badass motherfucker tween he is! But then, after fixing all the bad things, he rolls back to his house, and his mom gets stabbed and dies in his arms.
Did I mention this is another classic CLAMP production? In which every male character loses, or has already lost, an eye?
The thing that gets me about Kurogane is he has the focus of a missile. They're doing this massive adventure, spanning hundreds of worlds, and the whole time, Kurogane is literally just going, is this going to make me stronger and/or get me back to my town/princess? He doesn't care about the frills. He doesn't care about himself.
He is a weapon.