Monster Breeder - 58. Under the Mountain, Part 4: Lizardmen

This is a story that follows the courtship between a stone from Hell and a god from Heaven that begins in the underworld and spans for three lifetimes in the mortal realm.

The tens of thousands of universes have merged. The disintegration of spiritual force led to the momentous collapse of the great Cultivation World, a mighty era that had endured through millions of years of history. In the wake of the large-scale invasion of the Wilderness, the Avalon of Five Elements has become the practitioners’ last stand.

Being given a chance and reincarnated is nice and all, yet why do I have to become that male friend who just watches the protagonist flirting with his harem?---World: Kaguya-sama: Love Is War - Hyouka ----

I have a childhood friend.