That Time I Got Reincarnated as a Slime, Vol. 13 (light novel)

The Empire deploys a vast army over 900,000 soldiers strong to invade the Forest of
Jura. In response, Ramiris evacuates Tempest's inhabitants into the Dungeon for
safety. While Primal Demons Testarossa and Ultima duke it out with the Empire on the
front lines, the rest of the imperial army attempts to invade Ramiris's labyrinthine
shelter. Little do they know, however, that the only thing they'll find there is a
devastating bloodbath courtesy of Tempest's own mighty forces...