Dokin-chan, sometimes called Dokeen in English dubs, is an orange-red germ alien from a distant, cratered reddish planet. She acts as Baikinman's primary partner in crime and serves as a secondary antagonist. Her appearance includes green eyes, a single antenna, a long tail, a white face marked by a continuous orange line extending to her nose, small red cheeks, pink shoes, and white hands.

Her personality blends selfishness, greed, childishness, and demanding behavior; she frequently bosses Baikinman around to satisfy her cravings for food, items, or people. Despite this, she occasionally shows underlying kindness, especially in her protectiveness toward certain individuals. Dokin-chan possesses an obsessive, unrequited romantic fixation on Shokupanman, sparked during an incident involving stolen bread. This obsession drives extreme actions and elaborate schemes to win his affection. Her room houses vast collections of Shokupanman posters, plush toys, and handmade figurines, and she often daydreams about romantic scenarios with him. Tactics to attract him include ambushes, deceptive invitations, and manipulative ploys, like posing as an art teacher to force him into modeling exclusively for her. These efforts often backfire, causing unintended consequences or accidentally trapping characters like Currypanman, with whom she briefly forms a situational alliance.

Her relationship with Baikinman is complex; while she exploits his loneliness and subservience, forcing him into risky situations for her whims, she also harbors genuine, if hidden, concern for him. Rivalry exists with her younger sister, Kokin-chan, who shares the infatuation with Shokupanman, leading to conflicts over dolls and attention, though they intermittently reconcile. Dokin-chan initially used a specialized staff that could enlarge or shrink objects depending on the end used, but this tool saw inconsistent appearances and was phased out. Her primary transport is a pink UFO equipped with yellow-handed appendages, used for flight, carrying items like flowers or baskets, and occasionally capturing hostages during Baikinman's plots.

Across official media, her character exhibits minimal development, maintaining her role as a persistent, comedic antagonist driven by self-interest and romantic pursuit. She frequently flees confrontations at the first sign of failure.