Following the events of "Heir to Steel Armor", Ryūga Dōgai returns to the Eastern Region hoping to reunite with Rian, only to discover that the once-fertile land has been transformed into a vast desert by the Horror Garzas. As spiritual balance collapses, Ryume—the East’s Sentinel and guardian of the Dragon Gate—weakens as the eastern dragon nears its 500-year reincarnation. To preserve her life, she enters regenerative stasis and quietly chose Rian as her successor...