B. Ichi (B壱) is a manga series by Atsushi Ohkubo. It ran in the Shounen Gangan magazine from October 12, 2001 to May 12, 2003, and is complete in four volumes. Yen Press has licensed it for English release.
Most humans use only a small percentage of their brainpower, but a certain group of people called "dokeshi" can use a greater percent of their brain to unleash special powers, given one condition...For dokeshi Shotaro, that condition is doing one good deed a day. In exchange, he has the ability to use the powers of any animal by biting its bones. When Mana meets Shotaro on her travels, she expects nothing but trouble from the childish, ignorant boy-until he takes off into the sky like a bird. Mana may be impressed, but dokeshi are viewed as freaks by most of the population. And with the governor missing, all dokeshi are under suspicion. Ever-optimistic Shotaro refuses to be discouraged and journeys on with Mana in the name of Justice!