Tensei Shitara Slime Datta Ken: The Ways Of Strolling In The Demon Country

Story:

The Ways Of Strolling In The Demon Country:  Walking through Monsterland: The Spin-off are early about a guy who was born slime in another world. Attention, the story in the spin-offs is heavily ahead of the manga that's being published. So anyone who hasn't read the book risks catching serious spoilers.