In Jin Yong's novels there is a sweeper who is actually an unrivaled master.
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Thanks to Jin Yong's 天龙八部 (The Demi-Gods and Semi-Devils, 1963), 扫地僧 - the sweeper-monk at Shaolin who reveals himself as the strongest fighter - turned 扫地者 into a meme for an unassuming person hiding immense skill.