that is not even "power". it's just his heart beating so hard because kancheong (so-called the sound of King's engine), but he still manage to keep a straight face. coupled with his big built, most of the time it is the opponents that scared themselves off with King just standing there motionless.

in webcomic he almost got out-ed by atomic samurai but as usual, him not doing anything led to atomic samurai making his own conclusions.

also in webcomic, actually King did want to train himself but everybody else turn him away because they thought King being the strongest being, they cannot teach him anymore. Even Bang, who seems to know that King is a nobody (if i am not mistaken) turn him away.