Tuan Kirie is a Helix Inspector for the Japanese branch of the Admedistration, which governs society. She spends most of her time on peacekeeping missions to escape the stultifying nature of the normal world.

Spoiler

In her past she had entered a suicide pact with her two friends Miach Mihie and Cian Reikado into to rebel against society, but only Miach died.