Mikage Shiraishi is a central character in the anime Jewelpet Sunshine. He is a male student enrolled in the Plum Section of Sunshine Academy and the heir of the Shiraishi family, a household renowned for its expertise in ikebana flower arrangement. He was separated from his twin sister, Kanon Mizushirou, shortly after birth due to a birthmark that was seen as an omen of disaster. He grew up unaware of her existence until their reunion at the academy.

Mikage has fair skin, dark blue hair styled to neck length, and blue eyes. He typically wears the Sunshine Academy male uniform, which is mostly white with dark blue detailing. His personality is kind, highly tolerant, and respectful, though he tends to be somewhat withdrawn compared to his more boisterous classmates. This reserved nature is a result of his strict upbringing. Despite his calm exterior, he displays a snarky side, particularly when interacting with his roommates Masago Kuroda and Jasper. He is also polite and observant, often serving as a grounding presence amid the chaos created by the Jewelpets and his classmates.

His primary motivation is to support those around him, especially Ruby and Kanon. Both girls develop crushes on him, and he eventually becomes a romantic interest for Kanon. However, their relationship is complicated when they discover they are twins separated at birth, leading to a shift from romance to sibling bond. Mikage also has a deep connection to Jewel Land, which is revealed through his partnership with his Jewelpet, Granite, a gray cat representing endurance. This partnership activates his latent magical abilities and draws him into conflicts tied to his ancient Jewel Land lineage.

Mikage's role in the story is that of a love interest, a supportive peer, and a key figure in the magical conflicts. He is the focal point of a romantic triangle with Ruby and Kanon, and his twin revelation is a major plot twist. He is also rivaled with Jasper over curry, and they share a competitive yet friendly dynamic. Under the influence of dark magic, he transforms into a masked thief known as Phantom M-Kage, who charms girls and steals valuable objects. Ruby eventually snaps him back to his senses, and he later uses this form during the final battle against Dark Jewelina.

Throughout the series, Mikage undergoes significant development. He moves from being a reserved and somewhat mysterious student to a more active participant in both school life and the magical world. He reconciles with his twin sister, accepts her as family, and later develops romantic feelings for Ruby. In the epilogue, he uses Jewelina's magic to transform into a Lion Jewelpet named Granite, choosing to remain with Ruby forever. He is also shown to be skilled in kendo and academics, and he carries forward the Shiraishi family tradition of flower arrangement. His wry reactions to the antics of the Jewelpets provide comedic relief, but his thoughtful nature and hidden heritage make him a layered character whose personal journey intertwines with the larger magical conflicts of Jewel Land.