Mirai Shishio, younger sister of Tsukasa Shishio, endured a life-altering accident at six that left her clinically brain-dead, sustained only by her brother’s relentless financial support from his MMA career. Centuries later, her petrified form was revived during a truce between Tsukasa and Senku Ishigami, the petrification process miraculously restoring her health. Despite Tsukasa’s aged appearance, she instantly recognized him, embracing their reunion with heartfelt joy. Petite in stature, Mirai sports blonde bobbed hair, wide brown eyes, and a distinctive jagged scar encircling her head from petrification. She dons an orange sleeveless dress adorned with navy blue ribbons and simple sack-like shoes, crafted by Yuzuriha Ogawa. Her speech carries a Kansai dialect, rooted in her Osaka upbringing. Innately curious and fiercely loyal, Mirai balances childlike wonder with growing maturity. Initially captivated by the Kingdom of Science’s endeavors, she evolves into a responsible guardian of Tsukasa’s cryogenically preserved body following Hyoga’s betrayal, vigilantly protecting it during worldwide missions. She bonds with Suika and Ruri, contributing to community efforts like cotton candy sales post-currency revival. Discovering a passion for fashion, she aids Yuzuriha in design work while humorously blaming Tsukasa’s intimidating aura for her lack of romantic attention. By the story’s end, she thrives as a children’s fashion designer. Pivotal moments include reactivating the petrification device to heal Tsukasa in New America City, shielding others during a subsequent petrification event, and attending Taiju and Yuzuriha’s wedding. Her journey weaves familial devotion, rebirth, and quiet transformation from a protected child to a valued community member.