At the age of 16, he is known as The Shell Bullet in the anime and Kazuma "The Treasoner" in the manga. A Native Alter from the Lost Ground, he was initially classified as a Class "C" Alter User by HOLY but was later promoted to Class "A" after defeating Asuka Tachibana. However, during a violent clash with Ryuho in Episode 13, Tachibana suggests that their power must be at the Class "S" level to cause such devastation. Kazuma is regarded as the most dangerous Native Alter in the Lost Ground.
Kazuma is often reckless and shows little concern for his own safety. He will do anything for the right price, though he does care deeply for his close friends. He lives with Kanami Yuta, another Alter User, in an abandoned dentist's office. His rivalry with Ryuho is a central theme throughout the series. Kazuma is also a student of HOLY member Straight Cougar, whom he refers to as his "big brother."
Kazuma's Alter power is called Shell Bullet, which is an alloy fusion type Alter. In its initial form, his right arm is covered in a protective metal alloy, and three curved fins appear on his right shoulder blade. These fins disintegrate and propel him forward at high speeds. When a fin disintegrates, Kazuma shouts "Shocking First Bullet," "Annihilating Second Bullet," or "Exterminating Last Bullet" depending on which fin it is.
He has three main transformations, each adding more armor. His final form in the anime resembles a lion, with full-body armor and a tail-like protrusion on his back that allows for rapid movement.
Due to keeping his abilities and true employment secret, many people in the Lost Ground consider him a bum, coward, and lazy, especially in the early part of the series. Despite this, he responds with attitude and insults of his own. However, he respects and cares for those closest to him, like Kanami Yuta, whom he treats like a little sister. He keeps his secrets from them but lets them treat him as they wish.
