Kakeru Sakamaki (坂巻駆), also known as Sakamaki Kakeru, functions as the core mechanic for the main group. His duties encompass repairing and maintaining the mountain bikes (MTBs) utilized by Sho Yamato, Makoto Shido, and Ayumu Yamato, including crucial gear adjustments before their Idaten Battles, aided by a tool pouch worn on his waist.

He wears distinctive glasses, a striped t-shirt, and long green pants, and ranks among the most proficient MTB mechanics.

His personality combines kindness with deep MTB knowledge and high intelligence, often allowing him to grasp situations or solve problems quickly. While he occasionally feels undervalued, his dedication to supporting others remains unwavering.

Transported to the X-Zone alongside Sho and Makoto during their race against Team Shark Tooth, Kakeru honed his MTB expertise there and solidified his role as the group's primary mechanic. He later adapted Ayumu Yamato's specialized bike, the Imperial Dragon, for battle use.

He consistently safeguards an MTB reference book given by Yuki, a mechanic associated with the guardians of the X-Zone.