Tanktop Master/Synopsis

Alien Conquerors Arc
Tanktop Master is first shown at the S-Class Hero Association meeting. There, he recognizes Saitama's name, but is unable to recall where he had heard it.

During the alien invasion of A-City, Tanktop Master attempts to assist Tatsumaki in defeating the alien spaceship, but backs out when he realize that he was outmatched by Tatsumaki's psychic ability.

Hero Hunt Arc
Tanktop Master appears assisting his brothers and Mumen Rider against Garou. While battling and holding an edge over Garou, Tank Top Master has a somewhat fishy and familiar feeling about Garou, having his instincts tell him to finish Garou off because of Garou's villainous aura. This continues until Mumen Rider stops him from finishing Garou because Mumen Rider believes Garou has already taken enough of a beating. Although his brothers disagree, Tanktop Master agrees and allows Mumen Rider to tell Garou not to hunt heroes again. However, Garou chooses not to stop, stating his plan hasn't changed a bit. This leads to Tank Top Master attacking Garou again, but this time Garou decides not to hold back. No longer holding back, Garou manages to easily subdue Tanktop Master with his techniques. Afterwards, Garou reveals his identity to Tanktop Master. Tanktop Master and Mumen Rider attempt to stop Garou from brutally injuring Tanktop Master's brothers. Unfortunately, they are no match against Garou's Water Stream Rock Smashing Fist. Tanktop Master's brothers attempt to stop Garou on their own but are easily beaten down as a result. At the hospital, he's in the same room as Mumen Rider who was being visited by Saitama, who starts discussing Garou's appearance and abilities. Later, Tanktop Master joins the discussion, stating that it was Garou's fluid technique that made him so well-suited to fighting the heroes, who were otherwise more used to monsters leveraging their brute force to bring about destruction. Saitama recalls Tanktop Master's name, but only remembers him as "the guy who got beaten the hardest", much to Tanktop Master's annoyance. Tanktop Master then goes into detail about Garou's ability to turn a hero's power back on himself, no matter how much power he may possess, causing Saitama to be excited at the prospect of fighting a worthy enemy.

Super Fight Arc
The hospital where Tanktop Master and Mumen Rider are staying at was attacked by the monsters from the Monster Association. While protecting patients Mumen Rider is injured by the monster Gyoffrey and Tanktop Master saves him just in time by blowing the monster away with his Tanktop Tackle.

Monster Association Arc
He is seen talking with the remaining members of the Tank Topper Army about the current state of affairs.