Koyuki Takamine is a supporting character in the anime adaptation of Happiness!. She attends Mizuhosaka Academy as a member of the magic section and is one year above Haruhi Kamisaka and Anri Hiiragi, with whom she shares a close friendship. Her magical partner is a wand named Sphere Tom, commonly called Tama-chan, which takes the form of a staff topped by a small green floating sphere with a visible face, allowing it to speak and express opinions directly rather than through spiritual communication as other wands do.

Koyuki inherited the craft of creating Tama-chan replicas and puts considerable care into hand-making each one. Despite their nearly identical appearance, she can recall the exact order in which she produced every individual Tama-chan, a detail that underscores her meticulous and devoted nature. Much of her magical skill is focused on divination and fortune telling, areas in which she demonstrates notable proficiency.

Her bond with Tama-chan forms a meaningful part of her personal story. In one episode, Tama-chan briefly feels overlooked among the many copies and leaves; Koyuki’s heartfelt search and the reconciliation that follows reveal how deeply she values the wand, and the experience deepens her appreciation for her creations. Her role in the story is generally that of a reliable and slightly older friend who offers guidance and magical assistance to Haruhi and Anri, drawing on her knowledge and steady temperament. Through these interactions and her commitment to her inherited craft, Koyuki’s quiet dedication and the strength of her attachments become evident.