Kentaro Mahara

A Gunpla Fighter whose activity is based in America. With his great intellect, he conducts all kinds of research and analysis into Gunpla Battle. Using an original AI system of his own creation, he has performed repeated simulations to steadily build up his strength.

He is revealed to be the masked man who controls the mysterious "Runner Prison" system. Kentaro seems to have a strong preoccupation with Takuma.