Bofuri: I Don't Want to Get Hurt, so I'll Max Out My Defense., Vol. 12 (light novel)

Sunken ships, lost treasure, and underwater adventure! Maple Tree arrives on the eighth stratum to find a whole new world under the sea. They-ll have to dive deep to explore and master fighting in the water. Maple-s defense build isn-t designed for the speed and agility required to swim, but she-ll find a way! Thankfully Sally-s already a skilled swimmer. With her help, the rest of the guild heads out to find what awaits on the ocean floor-and what lurks in the dark depths...