Nanna is Yu Kananase's childhood friend, reuniting with him after he joins the International Military Organization (I.M.O.). She becomes a fellow test pilot candidate alongside Yu and Wolf in the Rim Hugen mech training program. Her father holds a leadership position within the I.M.O., serving as the superior to a by-the-books general; both are part of a high-level group analogous to the SEELE council, situating her within the I.M.O.'s command hierarchy.

Her name directly references the Norse goddess Nanna, reflecting the series' incorporation of Norse mythology alongside elements like the Loki mech, the Odin-named Ordian unit, the Gungnir Spear, and the Ragnarok computer system. She participates in the escalating conflict of the story's second half, encountering the "Remake" soul-transfer technology and Wolf's brainwashing into the Eric personality by the vengeful former partner of Yu and Kaori's father.