*"Great Demon Lord" Rimuru Tempest, formerly known as Satoru Mikami, is the main protagonist of Tensei Shitara Slime Datta Ken.

A partner and best friend of the True Dragon Veldora Tempest, Rimuru is the founder and King of the monster country Tempest. He is also a true draggon(unofficial).He is regarded as one of the strongest Demon Lord among the mighty Eight Star Demon Lords and also the one of two proper Great Demon Lord currently.

He has a kind heart and quirky personality. Even though he is quite laid back and wants to avoid troublesome situations as much as possible, he actually works very diligently when there is a task needed to be taken care of.

Rimuru tends to react very severely when there's a danger to his close ones, such as his countrymen, subordinates, (possibly due to the soul-link he shares with them), good friends, and students (he can't stand children suffering). One might say he overreacts to these cases, but it simply shows how deeply he cares for them, as a stark contrast with his usual cheerful self.

Unlike many other shounen protagonists, he has no problems with decimating any forces who dare to harm his subordinates and his country, regardless of their numbers, realizing full-well about the deed he's done.

After a mishap of subsides, Rimuru tends to quickly revert back to his laid back self and mentally (or even in actuality) scratches his head at the scenery he caused.

He is described as cautious and cunning by other fellow Demon Lords, unaware that it is simply a means of him trying to prevent troublesome situations from going out of hand. As he progresses through the story, he slowly becomes more and more like a actual Demon Lord, and as he adjusts to the rules of the new world and understands the capabilities of his subordinates, he begins to let them handle tough situations on their own instead of voluntarily diving in first to patch stuff up.*