Gou-yan is a male character and a classmate of the protagonist, Kotaro Kawaii, in the anime Puniru is a Kawaii Slime. He is a close friend of Kotaro, and the two share a bond as self-proclaimed introverts with a common passion for otaku culture, particularly idols and anime.

His personality is defined by a strong sense of common sense and restraint, which makes him the sensible counterpart to the more eccentric members of his social circle. He is often the voice of reason and is quick to deliver witty retorts and snappy comments from the sidelines, typically acting as the straight man in comedic situations. Unlike his friend Hone-chan, who has extreme and unrestrained otaku tendencies, Gou-yan keeps his desires and interests in check, preferring to observe interactions rather than take center stage. Despite his reserved nature, he is still a typical middle school boy and is not above enjoying light-hearted mischief.

While Gou-yan does not actively seek the spotlight, he frequently finds himself unwillingly drawn into the bizarre events and plans concocted by his more outrageous friends. He admires and perhaps envies the playful, comedy duo-like banter that Kotaro shares with the magical slime, Puniru. A notable and recurring gag in the series is that despite being the most normal member of the group, Gou-yan is often the subject of unexpected and risqué fanservice, frequently ending up unclothed or in embarrassing situations for comedic effect. His role in the story is to serve as a grounded reactor to the surrounding chaos, delivering much of the series' understated humor through his facial expressions and one-liners.