Chase ( Cheisu?) is one of the main characters in the series, Kamen Rider Drive. As a Roidmude that is not under the promised numbered 108 labeled as Proto-Zero ( Puroto Zero?), Chase was the original Kamen Rider prior and during the events of Global Freeze. After being subdued, Chase was forcefully reprogrammed and experimented on by Heart, Brain, and Freeze. After Global Freeze, he becomes a puppet of the numbered Roidmudes tasked to fight against the second Kamen Rider under the Kamen Rider-like form, Mashin Chaser ( Mashin Cheis?, lit. "Advance Demon Chaser"). However, Chase slowly regains pieces of his memories and resists the alterations made to him by the other Roidmudes to the point where he ultimately decides to start over, joining his successor and former mentor Krim Steinbelt in their cause to defeat the Roidmude as Kamen Rider Chaser ( Kamen Raid Cheis?).Chase was originally an assistant to Krim Steinbelt and the original user of the Drive Driver, under the name Kamen Rider Protodrive ( Kamen Raid Puroto Doraibu?). Prior to Global Freeze, he and Krim tested out Drive's power, but shortly realized that Drive was still underpowered to fight against a Low-Class Bat Roidmude and is unable to destroy their cores. When Global Freeze is initiated, Chase mobilizes all available Shift Cars to aid him against the armada of Roidmudes, saving Kiriko Shijima, butwas later defeated by HeartWith his Shift Speed Prototype Car confiscated by Heart, he eventually is re-programmed by Brain, taking the name Chase and receives powers based off Protodrive, assuming the identity of Mashin Chaser. He is then employed as an overseer/bounty hunter to Roidmudes and will destroy their bodies (but not their cores) in the events that they become a liability.

Chase's memories get altered by the Roidmude trio.It was later revealed that Heart and Freeze had also played a part in reprogramming Chase, when Chase used the prototype Speed Shift Car in the Break Gunner to regain his past memories