These are very rough since I had Kousaka and Frau give me a general idea of what's going on. Besides, Tokage is only three volumes long.
-The person Tokage ate was called Kazura/Katsura
-She was Tokage's twin
-Tokage suffered from some kind of skin disease/deformity?
-The villagers wanted to sacrifice Kazura to save the village
-Kazura was a miko and sacrifice elevates a miko into godhood.
-When Tokage ate some of the sacrificial food that was meant for Kazura, he started dying.
-Kazura then killed herself and told Tokage to eat her.
-Tokage then possessed Kazura's body and escaped.
-Tokage's body is said to possess mystical healing powers.
-Shinobu is also the reincarnation of Kazura. The shrine is meant to shield his powers.
-Another god ends up possessing a student in Shinobu's class.
-This god wants Tokage to suffer. I assume he's the one who cursed Tokage.
-TOKAGE GETS CLAMPED A LOT.
-Shinobu is badly injured.
-Tokage uses her blood to heal him. The other god vanishes since it's taboo for a God to injure a human.
-The curse is lifted!
-Tokage is... now a man stuck in a woman's body. HILARITY.
-Shinobu stops calling Tokage "Yuuka" and starts calling her "Tokage" around volume three.
-WE ARE DOUBLE THE INCEST. WHO KNEW?
No chance of us canon updating until the scans catch up to this point though. GDIT.