Inside the Tentacle Cave manga volume 1 features story by 
Umetane and art by Abi. 

Deep in the tunnels of an abandoned mine lurks a demon that absorbs the power of anything it touches: the Black Ooze. When it consumes its first human male, it acquires both intelligence and ravenous sexual desire, much to the distress of a sorceress who mistakenly enters its domain. The heroes who seek glory and riches in these caverns are about to learn why monsters should be feared!

Inside the Tentacle Cave manga volume 2 features story by Umetane and art by Abi.

Consuming adventurers and bending female mages to its will, the Black Ooze grows in both power and hunger. Frederica and Fiana, warped by demonic lust, hatch a plan to lure fresh bodies into the mines—and they’re on the verge of success! Is there any hope of escape for Satia and the other victims?!

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.