The Half-Demon Princesses befriend Rion, the only child of Beast King Kirinmaru of the Dawn, who had perished six centuries previously but had her spiritual essence perpetually bound to the earthly plane by the deep obsessive fatherly love Kirinmaru still has for her. With her own strength and resolve to put a stop her father's ambition and bring forth the Degenerate Age foretold by the Sacred Tree of Ages, Rion sustains her spirit within an artificial body, and Towa receives the ancient Star-Slicer Flute that transforms into the supremely powerful star sword, Zanseiken...