Yuiga is first seen when Osamu visits Tachikawa Unit. He is extremely arrogant to Osamu and refuses to have him, even attempting to physically remove him, before being kicked by Izumi. Izumi and Tachikawa go on to point out his weakness compared to all the other A-Class agents in order to demoralize him. After, Izumi has Osamu battle Yuiga until he could defeat him 100 times before he taught the former about hybrid Triggers. In the end, Osamu could only win 48 times whereas Yuiga won 142 times.