Mai Yumekano, daughter of former Tokyo mayor Eigen Yumekano, occupies influential social circles through her family ties. She shares a residence with roommates Yui Takanaka and Tomomi Murashita. Initially an aspiring singer-songwriter, Mai dedicated herself to rehearsals during periods of stability preceding major societal upheavals.

Following the coup d'état executed by B.D., she abandoned her artistic pursuits to join the military hierarchy, ultimately ascending to become one of its highest-ranking officials. The coup's violence—including the murder of her roommate Tomomi Murashita—prompted her father to demand her return to the family home. This tragedy destabilized her remaining roommate, Yui Takanaka, fracturing their shared domestic life.

Her name embodies poetic symbolism: "Mai" translates to "dance," while "Yumekano" fuses "yume" (dream or vision) with "kano" (leaf).