B. Ichi

 is a Japanese manga written and illustrated by Atsushi Ōkubo and serialized in "Monthly Shōnen Gangan" in 2001–2002. Set in the city of Toykyo, the series focuses on humans known as "Dokeshi", whose abilities to use more than 50% of their brain power allows them to unleash special powers, provided they meet one unique condition each day. For the Dokeshi Shotaro, his condition requires that he do one good deed daily to gain the powers of any animal by biting its bones. After Shotaro meets the traveler Mana, they begin a partnership of journey in the name of justice!
The series was collected in four bound volumes which were released by Gangan Comics in Japan. The manga was licensed for distribution in North America by Yen Press, which released the series in English in 2008–2009. The creator, Atsushi Ōkubo, later became well known for his hit series "Soul Eater" and "Fire Force".
Plot.
Most normal humans use only 30% of their brains, but a group of people known as the "Dokeshi" can use 50 to 60% of their brains, and thus have special abilities. These powers, however, come with a price: the Dokeshi must observe certain restrictions. Ignoring these rules can lead to the loss of something precious from within. In young Shotaro's case, he has to stick to doing one good deed every single day! In the central town of Toykyo, he meets a girl named Mana, and together they go on a journey to find Shotaro's childhood friend Emine. Will Shotaro be able to do good daily or will he succumb to laziness on his journey?