The king of Natra has fallen ill, leaving the only hope for his kingdom to his son, Prince Wein Salema Arbalest. Known to be capable and wise, he is the perfect candidate to become the prince regent. However, if the prince has anything to say about the matter, he would rather sell off the Kingdom of Natra to the highest bidder! Since he wields the authority of the throne, no one can stop Wein from auctioning off the country and using the profits to retire in comfort. All he needs to do is raise the value of the small kingdom to maximize his gains. But whether Wein's grand plan will succeed remains to be seen, as his wit often surpasses even his own expectations—much to the benefit of the oblivious citizens of Natra.

In Raja, a small country located to the west of Tempest. Rimuru and his companions get involved in a long-running conspiracy that swirls around the mysterious power of the queen. Rimuru and his commander Benimaru also encounter another ogre survivor named Hiiro, a man that used to be the brother of Benimaru. (Source: ANN)

Thirty-seven-year-old Satoru Mikami is a typical corporate worker, who is perfectly content with his monotonous lifestyle in Tokyo, other than failing to nail down a girlfriend even once throughout his life. In the midst of a casual encounter with his colleague, he falls victim to a random assailant on the streets and is stabbed. However, while succumbing to his injuries, a peculiar voice echoes in his mind, and recites a bunch of commands which the dying man cannot make sense of. When Satoru regains consciousness, he discovers that he has reincarnated as a goop of slime in an unfamiliar realm. In doing so, he acquires newfound skills—notably, the power to devour anything and mimic its appearance and abilities. He then stumbles upon the sealed Catastrophe-level monster Storm Dragon Veldora who had been sealed away for the past 300 years for devastating a town to ashes. Sympathetic to his predicament, Satoru befriends him, promising to assist in destroying the seal. In return, Veldora bestows upon him the name Rimuru Tempest to grant him divine protection. Now, liberated from the mundanities of his past life, Rimuru embarks on a fresh journey with a distinct goal in mind. As he grows accustomed to his new physique, his gooey antics ripple throughout the world, gradually altering his fate.

The story takes place between the first and second season, where Rimuru confronts the swirling conspiracies in the Coleus kingdom. (Source: MAL News)