Tenjouin Katsura, adopted daughter of Kaoru Yamamoto, was entrusted to his care as an infant after her escape pod—launched from the ruined Planet Noah—drifted into another dimension via an experimental tunnel discovered by Daigo Hoshiwatari. Her extraterrestrial origins remained hidden throughout her upbringing, per Daigo’s request.

With striking green hair cascading to her hips, vivid purple eyes, and a penchant for accessories like earrings, caps, gloves, and ribbon ties, Katsura’s vibrant appearance mirrors her buoyant personality. Her infectious optimism and knack for resolving tensions make her the emotional cornerstone of the YAT team. Sheltered by Yamamoto’s overprotectiveness, she retains a guileless innocence, oblivious to teammate Goro Hoshiwatari’s lingering affection until his blunt confession finally pierces her naivety in the series’ finale.

Blessed with Noahian physiology, she wields staggering strength—effortlessly lifting 100-ton objects single-handedly—and combat reflexes activated by perceived danger, sharpened further under Yamamoto’s tutelage. Yet her culinary efforts, notoriously perilous, prompted the crew to unanimously revoke her kitchen privileges.

Her bond with Yamamoto borders on symbiotic; his fierce guardianship nurtures her childlike wonder, while she vigilantly counters his reckless habits with earnest concern. As YAT’s charismatic ambassador, her likeness dominates promotional campaigns, drawing clients with her approachable charm.

Over time, she unravels the truth of her interdimensional heritage and adoption, while her dynamic with Goro matures from camaraderie to mutual affection. Unbeknownst to her, Yamamoto’s founding of YAT was driven partly by a quest to trace her biological roots, cementing her inadvertent role in shaping the organization’s destiny.