Master Pho was Agent K's karate teacher in The Replacements, but he turned out to be evil and was defeated by Agent K.
History
He first appeared in "Master Pho" when Todd replaced his karate teacher with him and realizes he's one of Agent K's enemies. He later returned in "Puzzle Me Daring" wearing a disguise stealing many things like artwork and money, leaving riddles that nobody could solve "except for Todd" and together Agent K and Todd defeated Master Pho. His appearance in the show was "Irreplaceable" when Dr. Scorpius had mind-controlled all of the replacements Todd and Riley asked for and joined and Dr. Scorpius in the Arctic at the end of the episode.
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