Hidetoshi Dekisugi, known as Ace Goody in English adaptations, is Nobita Nobi's classmate. He consistently achieves perfect test scores and excels across academic, athletic, and artistic domains. His talents include sports like baseball and soccer, realistic drawing, stage magic, sleight-of-hand tricks, and cooking. His surname meaning "overachiever" reflects these multifaceted abilities. He possesses a modest, polite, and rational personality, favoring scientific explanations over superstition. Dekisugi consistently defends Nobita from bullying by Gian and Suneo, emphasizing respect and individual societal contributions above academic results. He maintains a friendly attitude toward Nobita despite Nobita's jealousy and occasional attempts to sabotage him using Doraemon's gadgets. His relationship with Shizuka Minamoto involves shared intellectual pursuits like studying, reading, board games, outdoor painting, and cooking. He openly acknowledges liking her but refuses to use gadgets to influence her feelings. As an adult, he proposes marriage, but Shizuka declines, believing he does not require her support. He later encourages Nobita to ensure Shizuka's happiness before their wedding. Rare instances reveal vulnerabilities: he exhausts himself solving puzzles created by Nobita and Suneo; he becomes the target of prank calls from a jealous classmate seeking to undermine his academic performance; and he momentarily abandons rationality by mistaking Nobita for a supernatural entity. These situations resolve through his perseverance or forgiving nature, such as offering tutoring to the classmate who harassed him. In one alternate reality depicted in the "Parallel World" manga episode and its adaptations, his counterpart is unintelligent, scores zero on tests, and is bullied. His future includes becoming an astronaut, marrying, and fathering a son named Hideyo.