Kinnikuman II-sei (2002) (TV Series, 51 episodes, AniDB)

Requested on Jan. 30, 2022, 8:21 p.m.

Kid Muscle (or Mantaro for short) is a bumbling, gross, and wimpy sort-of person. Unfortunately, he has been summoned to protect the earth from the evil dMp, a band of cheating wrestlers from outer space. Luckily he`s not undertaking this task alone. Kid Muscle must join the Muscle League, a group of wrestlers from outer space who are training themselves so they can defend the earth, and stop the dMp by acheiving Ultimate Muscle, a hidden power that makes Mantaro an almost unbeatable opponent. Source: ANN