+1 for Bone.
Or Clan Apis
if he's cool enough to not think its dorky. (because it's awesome). At that age it might seem to little-kid to his tough teenager sensibilities. Usagi YoJimbo
, if you want to get him started on an awesome series.
If you don't mind more violence, of the ritualized sort, Lone Wolf & Cub is sure to satisfy a teenage boy
I read Akira
around that age, and I turned out fine. Grown man, playing with little metal dolls. . . well.. hmm.