Isekai Tensei Dungeon Master: Onsen Dungeon wo Tsukuru

COME ONE, COME ALL, TO THE MOST POPULAR DUNGEON AROUND! So there I am on my death bed when a literal devil comes to make a deal with me. I get a second shot at life, and in exchange, I'm on the hook for designing the most enticing dungeon her world has ever seen. Pretty sweet deal, if you ask me. Let's see, how do we get people to explore the dungeon? How about if we offer hot springs capable of rejuvenating skin, reversing the effects of aging, and granting you crazy strength? Whoops… Looks like our baths are too popular and are causing some geopolitical strife. Well, it's just another day in the life of a dungeon master! (Source: Yen Press)