Kajika, a 15-year-old steam smith, operates alongside close companions Ikoma and Takumi aboard the fortified steam locomotive Koutetsujou, traversing lands besieged by Kabane. With brown hair, brown eyes, and a height of 1.65 meters, she dons standard steam smith attire while overseeing the boiler room’s critical systems. Her compassionate nature fosters deep connections with fellow survivors, especially three orphaned children she shelters and nurtures. Though she radiates warmth, Kajika privately questions her own courage, quietly aspiring to mirror Ikoma’s boldness—a contrast to her steadfast humility and protective instincts.

Six months after the main events, *The Battle of Unato* reveals her nurturing role further as she mentors Mumei in knitting, aiding her in crafting a replacement for the green memento stone Ikoma gifted her. Kajika gently teases Mumei about the heartfelt implications of Ikoma’s vow to restore her humanity, blending perceptiveness with playful humor. During a perilous mountain shortcut, she and Takumi endure confinement in the boiler room, troubleshooting mechanical crises under pressure. While not a combatant, her technical expertise and composed focus prove vital to the group’s survival. Consistently prioritizing emotional and physical safety, Kajika anchors the Koutetsujou’s community, channeling her resilience into shielding the children and sustaining hope amid relentless adversity.