Kaseki Sousei Reborn II: Monster Digger

On that day, I set foot on "Hokora", which has long been said not to be entered. According to a strange doctor who lives in the town, a mysterious underground world inhabited by unknown creatures spreads out beyond the hole of "Hokora", and fossils with life are buried in it ...・. Apparently, the guy next door, who is always fighting, went looking for a legendary monster. "Let's lose! I'm going on...