Mirei lives an idle life of luxury, fawned over by male followers inside her stronghold in Mobius' Marine Resort.

She is an arrogant and selfish debutante who behaves as though she is the center of the world; however (except for her personality) she truly is exceptional at everything.

She boasts an immense popularity based on her goregous appearance and exceptional musical genius.

She is so obsessed with being number one that she even sees µ, the absolute idol inside of Mobius, as her rival.