King

King appears intimidating because his anxiety rarely shows clearly on his face. In reality, he is cautious, easily frightened by genuine danger, socially reserved, and acutely aware that the expectations placed upon him exceed his abilities.

He is also thoughtful and compassionate. King offers Saitama surprisingly insightful advice about heroism and personal growth, treating him like an ordinary friend rather than the world's strongest fighter.

His love of video games is one area in which his confidence is entirely justified. King is an exceptionally skilled gamer and defeats Saitama repeatedly even when deliberately handicapping himself.

King possesses no established supernatural combat ability. His legendary reputation is so overwhelming that monsters sometimes surrender or flee before he has to fight.

The King Engine is actually the loud pounding of his heart when he is terrified. Other characters interpret the sound as an indication that King is preparing to release his full power.

King's most consistent practical advantage is extraordinary luck. Coincidences repeatedly cause genuinely powerful people to appear around him or make opponents misinterpret harmless actions as terrifying demonstrations of strength.

His gaming skill is genuine and extreme, allowing him to dominate competitive games even against highly skilled opponents.

King initially appears whenever major monsters have already been defeated, causing the public and Hero Association to attribute those victories to him.

Saitama eventually discovers that King is an ordinary civilian who repeatedly happened to be present when Saitama defeated monsters before becoming officially recognized. King admits that he accepted credit because he was too afraid to correct anyone.

Rather than exposing him, Saitama begins visiting King's apartment to play games. Their friendship gives King one of the few relationships in which he does not have to maintain his heroic reputation.

During the Monster Association battle, King walks directly into confrontations with several Dragon-level monsters and survives largely because they interpret every nervous gesture as evidence of an unimaginable technique. His presence repeatedly buys the other heroes critical time.

Saitama is King's closest friend and one of the only people who knows that his reputation as the strongest man is based on a misunderstanding. They regularly play video games together.

Genos respects King as one of the supposedly strongest S-Class heroes and frequently interprets his ordinary behavior as evidence of hidden mastery.

Tatsumaki treats King with unusual respect because she believes his public reputation is genuine.

Atomic Samurai becomes curious about King's supposed swordsmanship and interprets his inability to draw a sword as evidence of technique beyond comprehension.