This has felt like Solo Leveling since the start, the mother is replaced by the sister here, but both revolve around the MC being basically the weakest that somehow becomes the strongest, and if this chapter is anything to go by, then both surround dungeons created by some kind of godly beings fighting each other through games where the humans are the pieces, and each godly being gets to select a chosen "Hero" to represent them, giving some of their own powers to their selected.
I guess it remains to see whether this newfound power and status causes the MC's personality and behavior to change, as well as his looks. I hope not, at least not as much and drastic as Solo Leveling's MC.