Mahoro Mikogami, the adopted daughter of Dr. Masahiko Mikogami and younger sister to Yamato within the ASY organization, conceals her true identity as Banka, biological daughter of the ancient fairy Shikari Sennyo, leader of the Shiromorishu. She infiltrated the Mikogami family under a human guise as part of her Shiromorishu mission.

Initially presenting herself as a supportive sibling to Yamato, Mahoro's concealed origins and conflicted loyalties emerge, complicating her feelings toward him and creating internal tensions within ASY. This emotional conflict transforms her role from a seemingly benign family member into an active destabilizing force.

Her abilities include levitation, high jumping, teleportation, and generating energy-based weapons like transforming her earring into a blue energy blade. She wields extendable scarves for combat and projects red energy blasts from her hands. Her capacity to maintain a convincing human disguise proved instrumental in infiltrating ASY.

Mahoro/Banka's actions serve the Shiromorishu objective to destroy the Fairy Bones powering ASY's Gousen mechs, bones harvested from Shikari Sennyo's corpse. This mission opposes ASY's operations and pits her against Rouran, the fairy sent to eliminate Shikari Sennyo and reclaim the Fairy Bones.

Her arc culminates in summoning Kakou Sennyo, a white Strange Steel Fairy approximately twice the size of Rouran's Kikou Sennyo, utilizing it in later conflicts. This act signifies her full embrace of her heritage and role within the Shiromorishu hierarchy.