So, a setup chapter. There's really not much to comment about here, we're just re-establishing everything we already knew except with additional world building that honestly nobody really cares about because it's deviating from the main purpose here which is an ugly stupid bastard and a goblin slayer goblin who evolved into being an intelligent goblin are playing with busty mommy figured girls in a death game about escalating sexual activities.
But it would be hilarious if the world building actually ends up becoming a serious thing and we deviate away from the original premise of the story... Which would be a really weird bait and switch. It's not what readers signed up for. I mean, Slave Harem in The Labyrinth of the Other World does pull the whole let's very slowly do a lot of world building. But it's at least still part of the main premise, the Labyrinth of the Other World. And it never deviates from how everything is the side quest to the main piece being seggs, lots and lots of seggs.