Katsuma Shimano, a young resident of Nabu Island, sports light brown curls, warm brown eyes, and a dusting of freckles across his nose. He dresses in practical island attire: blue overalls layered over a white T-shirt, light blue sandals, and a wide-brimmed sun hat adorned with a blue band and pale stripe. His yellow messenger bag, bearing a prized Edgeshot pin won from a hero-themed magazine raffle, accompanies him everywhere. A handmade floral charm bracelet encircles his left wrist—a twin to his sister Mahoro’s, crafted by their mother as a lasting bond. Katsuma’s Quirk, Cell Activation, enables him to accelerate cellular regeneration in others through touch, promoting healing or temporarily boosting physical capabilities. While most potent on individuals with blood types O, A, or B, its adaptability surpasses his father’s blood-type-restricted variation. After their mother’s passing and their father’s prolonged work absences, Mahoro became Katsuma’s primary guardian. Though she doubts the safety of his Quirk for heroics, Katsuma’s reverence for heroes fuels his dream to join their ranks—a passion embodied by his cherished Edgeshot pin. When the villain Nine targets his Quirk to reverse a terminal condition, Katsuma volunteers to relinquish his power to safeguard Mahoro and the island. Amid the crisis, he channels his ability to heal wounded heroes like Izuku Midoriya and Katsuki Bakugo, demonstrating unwavering resolve. His journey from shyness to steadfast courage underscores a commitment to selflessness and his aspiration to inspire change.