Bofuri: I Don't Want to Get Hurt, so I'll Max Out My Defense., Vol. 13 (light novel) — Yuumikan

Maxed out defense meets an unyielding secret boss!The newly opened ninth stratum presents players with a choice between two kingdoms that will be the backdrop for a large-scale PvP battle. Right away, guilds form alliances and start scheming against their foes. Maple has her fair share of friends and adversaries, so she'll have to make tough calls on who to ally with and which kingdom to choose. To get an edge on the competition, Maple is doing what she does best -- wandering around until she gets into trouble! Unfortunately, she stumbles across a hidden quest that drains her MP and seals nearly all her skills! Will this challenge be too much for even her defense to handle?