A slime whose gender is neutral. (The human form resembles Shizue's feminine appearance, but the mind is closer to male due to the influence of Satoru Mikami from his past life.) A member of the Octagram and the leader of the Jura Tempest Federation. He is an all-rounder slime who can do almost anything. Raphael, residing in his mind, assists him. He dislikes harming people and has a soft personality, but becomes extremely angry if his comrades are hurt. He dislikes work and loves to play, so he leaves most of the administrative tasks to Rigurd. Since Rigurd is competent, it isn't much of a problem. He is 160cm tall with light blue hair and golden eyes, appearing as a girl around 16 years old. He possesses resistances and nullifications for most attacks, and his skills include Beelzebuth (Gluttony), Magic Sense, and Demon Lord's Haki. His goal is to create a place where everyone can live happily and peacefully.

One of the Four Heavenly Kings of the Jura Tempest Federation and the Commander-in-Chief of the Department of Defense. He is an Oni, 182cm tall, with red hair and black horns. He primarily fights using flames.

In charge of cultural affairs in the Jura Tempest Federation. She is skilled at cooking and tailoring. She is the shrine maiden of Tempest who can do everything. She has pink hair with white horns and red eyes.

One of the Four Heavenly Kings of the Jura Tempest Federation. She fights using a large tachi called Gorikimaru. She loves fighting and serves as Rimuru's first secretary. She is good at everything except cooking; her cooking is notoriously terrible. No matter how unruly she is, she obeys Rimuru's words without question. She has purple hair and purple eyes.

Rimuru's skill that assists him from within his mind. Raphael's existence is a secret.

Veldora Tempest. His human form is 210cm tall, and he can grow up to 100m in his dragon form. He is the Storm Dragon who was sealed in a cave for 300 years at the start of the story. After Rimuru consumed him with Gluttony and became a Demon Lord, the seal was broken and he emerged into the world. He lives as the boss on the 100th floor of the labyrinth created by Ramiris. Since few people reach the 100th floor, he spends his time shut in his room doing research or reading manga. He likes sweet and delicious things. He obeys Rimuru's words. He has blonde hair and golden eyes.

Noir, the Black, one of the Primordial Demons. He is an eccentric who doesn't care much for power. He has slightly psychopathic tendencies. He laughs with a 'Kufufufu' sound and hates being disliked by Rimuru above all else. Consequently, he never goes against Rimuru's wishes. Like Shion, he is one of those who deifies Rimuru. He has black hair and red eyes.

The military advisor of the Jura Tempest Federation. He is a master swordsman who teaches swordsmanship in Tempest. Before receiving a name from Rimuru, he was known as the Sword Ogre. He has white hair and white horns.

One of the oldest Demon Lords, known by the epithet 'Destroyer.' She usually lives in the Forgotten Dragon City, but she often acts like a childish brat, asking Rimuru to play with her when she is bored. She obeys Rimuru's words. She loves sweet and delicious things. She has pink hair tied in twin tails.

A man of few words who was assigned the role of a spy by Rimuru. He is in charge of monitoring the surroundings of Tempest and gathering information. He utilizes skills such as Shadow Step for teleportation, body doubles, and sticky steel thread to fight.