Puri-Puri Prisoner vs. Baquma

Listen, monster... before you pound your chest and boast... you should try to overcome this average adult male right in front of you.

Puri-Puri Prisoner vs. Baquma was the fight between the S-Class hero Puri-Puri Prisoner and the Demon-level mysterious being Baquma of the Monster Association.

Prelude
Several monsters all attack Puri-Puri Prisoner together with their respective elemental abilities. However, Puri-Puri Prisoner appears visibly uninjured, and the monsters are shocked that even with Gyoro Gyoro's battle compatibility analysis, nothing they attacked him with worked. Puri-Puri Prisoner explains to the monsters that his immense durability comes from his embracing of pain with love, dubbing it his Angel ☆ Hug. Terrified, the monsters retreat from the battle to let the cadres deal with the S-Class hero, but before they can leave, Baquma gets in their way and tells them Gyoro Gyoro and Orochi don't take kindly to deserters. One of the monsters goads Baquma to fight Puri-Puri Prisoner himself, and Baquma takes up this offer, but absorbing the monsters with his trunk and taking their abilities to use in battle himself.

Battle
Puri-Puri Prisoner is disgusted by this monster's lack of love, and watches as he becomes stronger and mutates in the process. Baquma displays a small amount of his power and fires a beam of energy at the hero. Puri-Puri Prisoner manages to withstand the attack. Baquma goes on to explain his digestive absorption abilities and claims to kill all of the heroes along with stealing their powers. Puri-Puri Prisoner, however, responds to Baquma that while he is an S-Class hero, there are others in his class that have power he could not begin to keep up with, and compared to them, he is just an average adult male. Puri-Puri Prisoner tells Baquma that if the latter wants to fight those heroes, he will have to surpass the "ordinary man" standing in front of him. After Puri-Puri Prisoner's explanation, Baquma proceeds to bombard him with multiple attacks using the powers he had absorbed from those monsters earlier. Baquma is amazed that Puri-Puri Prisoner is still standing even after taking those attacks, viewing him as a monster, although he notices that the hero's body is beginning to tremble from the pain of the venom and electric shocks. Baquma claims that while Puri-Puri Prisoner's spirit is strong, his body however can't keep up. Suddenly, Puri-Puri Prisoner touches a stone wall with his vibrating finger, and the entire wall gets pulverised from the excessive vibrations. Baquma is shocked, and asks him what did he just do. The S-Class hero replies by saying his love has managed to give birth to a brand new fighting style: Vibration ☆ Angel. Puri-Puri Prisoner unleashes his new attack: Vibration Dark ☆ Angel ☆ Rush, and rushes toward Baquma. The monster's final thoughts are that Puri-Puri Prisoner really is a monster, and he is utterly decimated by Puri-Puri Prisoner's attack, making Puri-Puri Prisoner the victor.

Trivia

 * This fight, along with several later battles, showcases a larger role for Puri-Puri Prisoner in the Monster Association raid. In the webcomic, the S-Class hero did not encounter any of the Monster Association's forces and did not see action until a particular encounter much later.
 * Given that Gyoro Gyoro assigned specific monsters to combat specific heroes, it is possible that he underestimated Puri-Puri Prisoner's strength and thus only sent Tiger-level Mysterious Beings after him.