So much plot, time to recap!
1) MC is kidnapping girls from the depths of a dungeon
2) MC is holding girls captive in a furnished item box.
3) Girls can only leave the item box by satisfying the MC with physical contact.
4) The MC will not enter the dangerous parts of the dungeon without dragging his sex slaves with him.
5) If the MC becomes the harem king of the dungeon, he will be immortal
6) Sex slaves can only become stronger by satisfying their master.
7) MC requires the slaves to strip daily for water play.