The legendary dragons, angels, mermaids, spirits and humanoids all once existed, and they were equal parts of the world with humans. A time of melee with knives, swords, guns, runes, rings, and flamethrowers. But for some unknown reason, the first five races, whose lifespans were far longer than those of humans, all disappeared at the same moment.
There are still survivors, these places have long become isolated peach blossom gardens, or the source of disaster. It is running there, and people have not known it for a long time. But there are some poor boys and girls who are burdened with a fate they shouldn't have to bear, and want to resurrect this miserable history.
"O ancestor who is unrivaled in galloping on the battlefield, please bring the power of the God of War and reappear."
"My noble archangel, please incarnate and return from your faith."
"Kind Ariel, come back from heaven and bring your immortal soul to revive the mermaid clan."
"A race in mythology that is burdened with both good and evil, please reappear before us."
"Humanoids and humans are one family. Forger, come back."