The Slime and the Demon King

Laster was once a human, but after reincarnating as a slime in a fantasy world, he finds himself happily serving at the side of the future Demon Lord. Yet the humans soon deploy a Hero, and everything changed after the human kingdoms attacked...

Note: Contains consensual sex between a demon and a human reincarnated into a slime. Assumes reader familiarity with isekai fantasy tropes. Multi-chapter work, but not all chapters have sex.

Warning: This story contains references to resurrection and touches upon the concept of life after death, as well as free will.