Scarlet Bond

That Time I Got Reincarnated as a Slime the Movie: Scarlet Bond (劇場版 : 転生したらスライムだった件 : 紅蓮の絆編) is a movie released on November 25, 2022. It was first announced on September 21, 2021, after the second season's conclusion.

This movie has sold more than 1 million tickets for more than 1.33 billion yen (about US$10.06 million).

Synopsis
Rimuru Tempest, a slime who evolved into a demon lord to save their friends. They and their friends established the Jura Tempest Federation, a land of monsters.

In Raja, a small country located to the west, A long-running conspiracy swirls around the mysterious power of the queen.

Then, Hiiro, a "Survivor of the Ogres", suddenly appears in front of Rimuru and friends.

They are reunited with a man who used to be the brother of Benimaru and his friends.

The severed "scarlet bonds" now become the guiding light for a new fight.

The Origin of Hiiro
A mercenary band of Ogre's attempted to make their escape at night but were ambushed by a band of Majin lead by Yamza. The ogre mercenaries were originally from ogre village in the Great Jura Forest and having heard that they were going to attacked by an Orc Army, wished to head back and reinforce them, but were denied, and thus forced to escape Clayman's forces, who they were currently employed to. A handful of ogre's barely managed to survive, including the ogre leader, and were found and treated by agents of the Kingdom of Raja. However, the only one who could be saved was their leader, as Queen Towa used the power of her tiara and the souls of his half-dead comrades to bestow him the name "Hiiro", to allow him to evolve.

Hiiro awakens 10 days later and learnt about what happened to him and his comrades. However, once he heard that he was unconscious for 10 days, he immediately ran out despite his injuries, stole one of the country's wyverns and flew it to his hometown, only to find it in ruins. Believing there to be no survivors, he breaks down, and after recovering he returns to Raja four days later.

A Messenger Arrives in Tempest
A few years later, Rimuru Tempest is now a Demon Lord and ruling the Jura Tempest Federation. Hiiro was sent to Tempest as a messenger, when he spotted the orcs working on the highway. Consumed by rage he attacked them, facing Geld in battle. Though they were on even footing, when Geld learnt his opponent was a survivor of the ogre village that the Orc Army destroyed, he gave up the battle and was about to allow Hiiro to strike him down, only to be interrupted by Souka and later Benimaru, the latter's presence stopping the battle for good. After the two oni reintroduce themselves with their new names, and Benimaru explains the orcs are citizens of Tempest, Hiiro soon reunites with the other Oni survivors, as well as meeting Rimuru himself.

At dinner the oni's reminisce their past, before Hiiro reveals his current allegiance to Raja, and the situation the country and their queen is facing. As it turns out, the small Kingdom of Raja, which resides at the edge of the Great Jura Forest, is on the verge of bankruptcy with their only source of wealth, their gold mine, being tapped out. Furthermore, toxins from the mines keep leaking into the lake, poisoning the waters and the land around it. This forced their queen to use the tiara to purify the lake, but as a result, was continuously afflicted by the tiara's Cursed Poison as a side effect. Seeking alternatives, Hiiro proposed cultivating the forest, though the elders are opposed as they do not want to incur Veldora's wrath. However, they soon heard the results of Tempest's war against the Kingdom of Falmuth, so Hiiro volunteers to be a messenger to negotiate with Rimuru to cultivate some of the forest. Hiiro then made his heartfelt request, as did his oni brethren, for his sake, though this was unnecessary as both Rimiru and Veldora easily agreed. Rimiru then offered to visit Towa to wish her well, which Hiiro enthusiastically agreed to.

Visiting the Kingdom of Raja
The following day, Rimiru accompanied Hiiro to Raja, taking Ranga, Benimaru, Shion and Shuna as escorts. Just as they entered the Kingdom, a mishap happened with the wyvern Shion was riding on (as it was knocked unconscious after inhaling the miasma emitted from Shion's cookies) causing it to plummet, leading to Ranga and Rimuru saving them, though they ended up wet after passing through a waterfall coming out from one of the mines. They then met with the kingdom's prime minister, Mobuji and revealed the good news of a successful negotiation and when they started discussing details on how to cultivate the land, Ramiris barged in with Treyni and Beretta. Rimiru decided to leave the details to Treyni, and wished to be granted an audience with the queen. Having met her and using Raphael to analyze her, he realized that though the Cursed Poison is uncurable by anyone other than the caster, her condition would naturally improve if she stopped using the tiara, rested and ingested some of Apito's Honey. After Rimiru gave his prognosis and had her eat some honey, the queen recovered a bit but lamented that she couldn't afford to stop using the item as long as the lake kept getting poisoned by the mine's toxins. However, Rimiru offered to fix that problem as well.

Relocating to the lake, Rimuru reveals that the poison did not originate from the mines, having analyzed the water from the waterfall when arriving in Raja earlier. Knowing that the poison had another source, Rimiru split the lake and walked through it to discover an old magic circle that was responsible for the poison. He then used Beelzebuth to consume not only the magic circle but all the water in the entire lake, purified it, and then spat the water back out, thus singlehandedly solving the Kingdom of Raja's problems. Later that night, while the kingdom celebrated with a festival Rimiru met with Towa in private, where she confided in Rimiru. She told him how she was envious of Rimiru for how open he was with his comrades, and the guilt she felt for Hiiro for tying him to her by saving his life and giving him a name, as she did it in hopes of gaining a confidante. Describing herself as calculating and selfish, Rimiru cheers her up that such a thing applies to everyone and that it's not a bad thing. He advised Towa that she was too serious and that she should lighten up and be more honest or else she would be crushed by her responsibilities.

A Conspiracy Unfolds
Sometime later, the merchant Lacua is shocked and in despair to see that not only is the lake purified, but the Raja citizens were cultivating the Great Jura Forest and Queen Towa has recovered.

Interview
An interview with Fuse, the author of the series, Taiki Kawakami, the artist for the manga, and Mitz Vah, the artist for the light novel, was conducted about their thoughts about a movie being announced.

"I started writing this piece of work as a hobby, but it's going to be made into a movie! I was so dumbfounded at first because it felt almost unrealistic. Please look forward to seeing how it will turn out!"

- Fuse

"The movie was confirmed......! This is all thanks to each and every one of you who have supported Tensura, and I felt that we similar to the citizens of Tempest that are supporting Rimuru. I'd like to thank you all and hope we can make a good movie!"

- Mitz Vah

"When I heard the news of a movie release, I can't stop being excited, and that there was more to Tensura that I don't know yet. I can't wait to see the more action from Rimuru and his friends in the movie version!"

- Taiki Kawakami

Trivia

 * Same as in Season 2 Episode 15, Veldora was seen reading chapter 21 of Trinity in Tempest, which is in Volume 5.