That Time I Got Reincarnated as a Slime season 3 ending explained: Why did the Council of the West send Rimuru Tempest a letter?

Rimuru Tempest, as seen in That Time I Got Reincarnated as a Slime season 3 (Image via 8Bit)

While That Time I Got Reincarnated as a Slime season 3 concluded on a fine note on September 27, 2024, the finale's final scene calls for some interesting discussion. The episode ended with the dignitaries from the Jura Tempest's neighboring nations returning to their respective homes after enjoying a grand reception from Rimuru Tempest at his town's Founder's Festival.

Rimuru also speculated that Yuuki Kagurazaka, the Free Guild's Grandmaster, was involved with the Eastern merchants. However, that's not all the ending had to offer. Before the end credits, Rimuru Tempest revealed that one month after the Founder's Festival, Jura Tempest received a letter from the Council of the West.

So, why did the Council send Rimuru a letter? Light novel readers would know that it was a conspiracy by Mariabell Rozzo, who sent the letter on behalf of the Council, inviting the Slime to one of the Council's meetings. Not only did she want to set the Slime into a political trap, but she also wanted to assassinate him.

Disclaimer: This article contains spoilers from That Time I Got Reincarnated as a Slime light novels.

That Time I Got Reincarnated as a Slime season 3 ending: Exploring why Mariabell sent Rimuru the letter on behalf of the Council

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Mariabell Rosso, the avaricious Otherworlder in That Time I Got Reincarnated as a Slime season 3 was driven by an intense desire to dominate everyone and rule over other nations. With her unique skill "Greed", she longed to control her subjects and raise the flag of the Rozzo family high.

However, Rimuru Tempest's status as the Demon Lord, his town's progress, popularity and fame, everything stuck out like a sore thumb, preventing Mariabell from realizing her dreams. That Time I Got Reincarnated as a Slime season 3 saw the girl taste failures a couple of times against Rimuru.

For example, her plan to use the Eastern merchants to spur a conflict between the Jura Tempest's Rimuru and Western Holy Church's Hinata Sakaguchi didn't work. Likewise, she couldn't destroy Rimuru and the Jura Tempest's reputation at the Founder's Festival.

Mariabell in That Time I Got Reincarnated as a Slime season 3 (Image via 8Bit)

Hence, she decided to destroy Rimuru once and for all. That Time I Got Reincarnated as a Slime season 3 finale saw the Rozzo family's head, Granbell Rozzo, leave the planning of Rimuru's downfall to her granddaughter. Interestingly, Mariabell knew Rimuru Tempest's desire to ensure a peaceful co-existence between the monsters and humans.

While the Jura Tempest's neighboring nations witnessed Rimuru's vision at the Founder's Festival in That Time I Got Reincarnated as a Slime season 3, some human nations still viewed the Slime's Monster Nation with puckered brows.

Rimuru Tempest, as seen in the anime (Image via 8Bit)

As such, Rimuru wished to join the Council of the West to strengthen his connection with those human nations and share the vision of a peaceful co-existence between monsters and humans.

Interestingly, the Council was founded by none other than Granbell Rozzo to address the looming threats from the monsters. The Council's role gradually evolved to check on the Eastern Empire's influence. As such, the Rozzo family had a huge grip over the Council.

Mariabell Rozzo, who is considered the strongest member of the Rozzo family owing to her unique skill, Greed, worked from the shadows. Thus, it would have been easy for her to pull the strings. After a discussion with Yuuki, she realized that it was best to invite the Slime to the Council of the West's conference for an audience.

She wanted to set Rimuru and his executives into a political trap, pinning the blame for Prince Elric Von Engrassia's assassination on them. However, she was unsuccessful. Additionally, Mariabel wanted to use Reiner to subdue and control Rimuru using the Orb of Domination.

However, the Slime removed the Orb's magic without destroying it entirely. Besides that, Mariabel planned another assassination attempt on Rimuru using Glenda, but she lost to Souei. Rimuru Tempest's cunningness and his executives' prompt response thwarted Mariabel's plan, as Tempest got recognized as a nation at the Council.