Inside the Tentacle Cave manga volume 3 features story by Umetane and art by Abi.

Fiana and Arfila, Knights of the Queen’s Guard, barely escaped from the slime caverns with their sanity. Regrouping at the palace, they are determined to return to the caverns and slaughter every last one of the slimes who violated their allies. But townspeople have begun to go missing in the night. A new nightmare is being born. The Black Ooze’s reach is spreading beyond the confines of the mine, spelling doom for the Kingdom of Fontilles and its citizens.