Yoroi Mikoto begins as Shirogane Takeru’s gender-ambiguous best friend in their school life, bonding over gaming and playful camaraderie. Classmates perceive Mikoto as male, but subtle clues—avoiding male communal baths, favoring feminine accessories, and donning girls’ uniforms during events—hint at a concealed female identity.

Transplanted into a war-torn timeline, Mikoto emerges unequivocally female as a cadet in the 207th Training Unit. Her survivalist prowess stems from childhood expeditions with her father, an Imperial Japanese spy whose covert missions she uncovers after his disappearance during a coup. These experiences sharpen her skills in wilderness navigation, trap dismantling, and tactical combat.

Cheerful yet scatterbrained, Mikoto radiates optimism amid warfare’s brutality while navigating self-consciousness about her androgynous frame and perceived lack of femininity. Her dynamic with Takeru shifts from tension over her timeline-altered gender to deep camaraderie, culminating in a vulnerable farewell letter where she admits romantic feelings, crediting him with bolstering her self-acceptance.

Physically, Mikoto’s slight frame, cropped blue hair with jagged bangs, and warm brown eyes—paired with a 156 cm stature—enhance her gender-neutral aura, amplified by military garb. The dual timelines’ gender discrepancy stems from her father potentially manipulating records to evade male conscription laws, shielding her from frontline duty.

Her story closes without clarifying the metaphysical roots of her shifting identity, a narrative enigma that distinguishes her from peers with stable existences, leaving her cross-world duality purposefully uncharted.