This was a world where all the firstborn disappeared overnight, everything changed.
Tsuki was traveling through dimensions, in which he was collecting the information and riches that the dead left, he went back to ancient temples that were abandoned among the dead that covered the streets.
One of the traveling sorcerers who were reporting to Um-Mu's council that kingdoms had fallen, so they should collect the worlds, while the dragon, the beast of the end, ate the ravaged worlds.
They should collect the remaining souls that still existed, before these worlds collapsed, it happened that if a world reaches its extinction, there is nowhere for souls to go but oblivion, if a world is destroyed, its dimension falls into ruin, the souls that exist there, have nowhere to go, they just disappear like the world in question.