The King of Tempest, a slime and a newly appointed Demon Lord. Generally mild-mannered and a person of character. He has a neutral appearance that can look like a young, beautiful boy, with long blue-silver hair and golden eyes—a beauty recognized by both himself and others. According to Veldora, his namesake and best friend, "Rimuru is basically serious and sincere, and hates lies, but in battles he cannot afford to lose, he will calmly execute any cowardly means necessary." He is the type to act as soon as he thinks of something. He is the type who is unconsciously popular with women and is dense about it. He has been with Guest since before the founding of Tempest. He fell in love with Guest at first sight when they met in the Jura Forest, and they started dating after his intense advances. Guest is his confidant and lover, and he is extremely overprotective. Though he usually hides it, he is surprisingly possessive, jealous, and dependent on Guest.

An Ogre with red eyes and red hair. He respects Rimuru. As Rimuru's right hand, he has a strong sense of justice and cares for his comrades. He is Shuna's older brother. He treats Guest like a child.

An Ogre. He respects Rimuru. Cool and taciturn, but actually kind. He specializes in espionage.

An Ogre. She loves and respects Rimuru and Guest. She especially goes out of control when it comes to Rimuru. She serves as Rimuru's first secretary. She is bright and energetic, but her cooking is disastrous. She is overprotective of Guest.

An Ogre. She has a kind and bright personality and is skilled at sewing and cooking. As Guest's caretaker, she is extremely overprotective and lives to spoil Guest, becoming somewhat clumsy whenever Guest is involved. She loves and respects Rimuru and Guest.

A Demon. Rimuru's second secretary who respects Rimuru and will do anything for his sake. He treats Guest like a child.

The leader of the Tempest Wolves who respects and swears loyalty to Rimuru. A magical beast who manipulates the power of powerful lightning and wind, and can move through shadows. Usually cool but cares for his comrades. He usually hides in Rimuru's shadow to accompany him. He is adored as a pet by Guest and treated like a dog.

An elderly swordsman of the Kijin race. A master of swordsmanship. He respects Rimuru. With a calm personality, he supports Tempest's military might as a mentor figure. He treats Guest like a child.

The youngest of the four "True Dragons" that exist in the world. A lonely, party-loving mood-maker. He possesses high intelligence backed by intense curiosity, but because he is a True Dragon, his pride is high and his thought process is simple and blunt. He immediately speaks his mind, often causing trouble. He is weak to flattery and easily manipulated.