Tsuyuha reigns as Queen of Evergreen, a magical realm plunged into crisis when perilous seeds are stolen and sent to Earth. To reclaim these seeds, she directly commissions agent Natsuki for the critical mission, later enlisting Hazuna as well. She maintains communication across dimensions, receiving updates from her agents and offering strategic guidance. Tsuyuha specifically confirms the recovery of three seeds while stressing caution regarding the remaining two, which hold greater strength and magical power. Her authority extends to figures like Bergamot, who faced consequences for eloping with a human and was later implicated in the seed theft.

Her leadership centers on safeguarding both Evergreen and Earth from the seeds' corrupting influence, which twists human desires to transform people into monsters. She identifies and empowers human allies, notably sanctioning Chihaya Hiiragi's transformation into the Magical Warrior Carmein to fight the seed threats. Though Tsuyuha makes few direct appearances, her influence shapes the overarching conflict through her agents' actions and the vital mission she commands.