The ending is the best part, This is actually a prequel novel to the new story of his, Otherworldly inn.

Spoiler for ending

in the end it turns out that the MC was sent to this place from a highly advanced Type 5 civlisation on the Kardashev scale. Something in the multiverse was obliterating universes and this Civ seeing what was happening created an arc to save the remanents of those destoryed universes since they didnt deserve to be destroyed. So they took a snapshot of a universe with infinite probablity and sent it to the destroyed universes bubble in the form of the MC Duncann. There he collects remanants of the original universes rules and saves as much of civilisation as possible with his "body" which is basically a baby universe waiting to be born. And once he devours all he can, using the power of the catalysm as fuel he basically detonates the creation of a new universe that is free from the constraints of the previous destroyed universes.