Dimensional Researcher Lias:
The Dimensional is already crumbling here and there, causing strange phenomena here and there.
The Makkum who has hidden inside the Dimensional Rift was probably the one injured while fighting the adventurers, while the timeline is rather complicated...
I think that Makkum, who was injured somewhere, has chosen this place to lick his wounds and gather up his remaining strength. I guess he expected it would be safe, since it,s not an easily accessible place.
It appears that he took various measures to further improve the safety. He put in place the shells of Lillim and Nephilim we kept encountering, and the dimensional monsters that were hiding out inside.
"What should I do then?"