Spirit Circle Vol. 5 (manga)

Newly awakened from a vision of the farthest future and reeling from the ramifications of what he saw, Fuuta is at risk of losing himself completely to the identities of his past lives. Rune has taken it upon herself to make sure he doesn't fall off the wagon. Yet only two lives remain before Fuuta has seen his entire spirit's journey. Grasping their spirit circles in hand, Fuuta and Kouko journey forth again, and find themselves in a situation they never expected...they're gender-swapped!