Yajirobe

Yajirobe first appears during the King Piccolo Saga as a wild mountain samurai who crosses paths with Goku. His swordsmanship is genuinely impressive; he easily kills Cymbal, one of King Piccolo's demon spawn, and later climbs Korin's Tower to deliver Senzu Beans to Goku. This establishes Yajirobe's recurring role: he lives at Korin's Tower, rarely fights, but delivers critical supplies and assistance at pivotal moments.

His single greatest contribution comes during the Saiyan Saga. After Vegeta transforms into a Great Ape and begins crushing Goku, Yajirobe sneaks up behind the giant ape and slices off his tail with his katana, forcibly reverting Vegeta to his base form. This act, performed by one of the weakest named characters in the series, arguably saves the entire planet. Yajirobe is terrified the entire time and immediately hides afterward, but his bravery in that one moment is genuine. He continues to reside at Korin's Tower throughout the series, growing Senzu Beans and occasionally descending to deliver them during crises, cementing his reputation as the most useful coward in Dragon Ball.