Moon debuted in 2011 as one of the four foundational LINE Friends characters alongside Brown, Cony, and James. His spherical head evokes a full moon, complemented by a small nose, black oval eyes, and a consistent wardrobe of white shirt, grey trousers, and red tie.

Personality-wise, Moon thrives as a mischievous "mess maker," deploying pranks when displeased and displaying stubborn, capricious traits that spark clashes with Cony. Workplace portrayals in "LINE Offline" emphasize laziness, while "LINE Town" competitions reveal cunning tactics. He shares Cony’s ENFP Myers-Briggs classification.

Origins remain enigmatic, with no confirmed species or point of arrival. Supplemental lore dubs him "Prince of the Moon" per his sister’s claim, though unverified. Romantically drawn to Jessica, their marital status in "All about Brown - Ep.06" is non-canonical. He shares a rivalry-fraught bond with James.

Narrative arcs include his temporary death via bear attack in Chapter 50 and supernatural Chapter 51 revival after offending Disper, guardian of the Realm of the Dead—resulting in banishment. Seasonal events like the "Brown and Friends" Halloween special feature his werewolf metamorphosis.

Extended characterizations note controversies involving sporadic nudity and suggestive conduct. Despite this, he persists as a classically popular franchise figure. His familial ties include two unspecified sisters.