Bofuri: I Don't Want to Get Hurt, So I'll Max Out My Defense., Vol. 16 (Light Novel) -

The exciting large-scale PvP battle was full of challenges, forging bonds and deepening friendships between Maple Tree and the other top players. Now that it has come to a spectacular close, the game admins announce the opening of the tenth stratum. The map is the largest yet, and the final boss is hiding somewhere in that vast area. Everyone is hyped to start exploring and pitch in to track down the boss. Sally and Maple kick things off by preying on the unsuspecting tenth stratum monsters. And when Maple acquires a new skill, this time it'll involve her...splitting apart!