That Time I Got Reincarnated as a Slime is a smash-hit isekai anime that features Rimuru Tempest, one of the strongest isekai heroes in recent memory. He was once Satoru the salaryman, but now he is the benevolent king of a monster nation and he understands the value of teamwork. Despite his many powers and abilities, he can only do so much alone.
By this point, Rimuru has made many good friends and powerful allies to back him up, and together, they make up the Jura Tempest Federation. Sometimes, Rimuru needs his friends and allies to support him during battle or in negotiations, but other times, Rimuru can handle everything himself.
10 NEEDED AN ALLY: When He Delivered A Speech In Dwargon
Rimuru Tempest soon learned that he needed more than magical spells and friendly words to run a kingdom. He also needs solid skills as a politician and orator, and, fortunately for him, King Gazel Dwargo provided some hints and insights for Rimuru to follow.
Rimuru listened closely to what the experienced Gazel had to say, and he did his best to deliver a rousing speech to the crowds in the Armed Nation of Dwargon. Rimuru couldn't have done this alone - he needed someone to guide him along, and he was humble enough to know it.
9 ACTED ALONE: When He Dueled Gazel Dwargo
One of the best duels in Season 1 was when Gazel Dwargo visited Rimuru's young kingdom in person to test Rimuru's grit and resolve. Gazel challenged Rimuru to a single duel of swords, and no one was allowed to interfere. This time, Rimuru's magic wouldn't save him - he had to win or lose by the blade.
Rimuru did his best, but Gazel had more experience and better technique with swords, easily being on par with the elderly Hakuro. In the end, Gazel called it off, and he was impressed with Rimuru's performance. This helped solidify their political alliance.
8 NEEDED AN ALLY: When He Fought Clayman During Walpurgis
One of the best battles of Season 2 pitted Rimuru Tempest against his worst enemy, the colorful Demon Lord Clayman, but this wasn't a solo fight for Rimuru. Although his fight was personal, Rimuru brought Shion with him, and he even received aid from Ramiris' golem, Baretta.
Rimuru and his allies took the fight to Clayman and his assorted minions, and, at one point, even Veldora the storm dragon intervened to fight on Rimuru's behalf, dueling Milim in bare-handed combat to buy Rimuru time to finish Clayman. This showdown was an outstanding group effort.
7 ACTED ALONE: When He Performed The Megido Spell
After the joint Falmuth/Church army assaulted Rimuru's city, Rimuru formed a plan to launch a fierce counterattack which involved mobilizing most of his best warriors, from Benimaru to Geld and Hakuro, among others. But they didn't directly aid Rimuru during this campaign - they had their own enemies to fight.
While Benimaru and the others kept the enemy army busy, Rimuru acted on his own, soaring high above the Falmuth/Church force and activating the fearsome Megido spell. With it, he easily dispatched thousands of enemy troops and harvested all of their souls to fuel his transformation into a True Demon Lord.
6 NEEDED AN ALLY: When He Hired The Dwarves To Build Up The Golbin Village
Rimuru was in desperate need of allies early in Slime, and even after he united the goblins and dire wolves into one tribe, he still had a lot of gaps in his developing nation. So, he and some goblin friends journeyed to the Armed Nation of Dwargon to hire some craftsmen and engineers.
As hoped, Rimuru returned home with four skilled dwarves, including Kaijin, an expert blacksmith. The four of them helped rebuild the goblin tribe with sturdy buildings, and later, Kurobe the ogre also lent Rimuru his expertise. Rimuru can do many things, but he can't forge a sword or build a house.
5 ACTED ALONE: When He Dueled Hinata Sakaguchi
Rimuru fought quite a few duels during the story of Slime, and one of these duels pitted him against the fearsome knight commander Hinata Sakaguchi. In fact, Hinata made sure that Rimuru fought her alone, with no allies to call upon. Not even Ranga could help Rimuru much.
Rimuru didn't want to kill Hinata, but she wanted him dead, and she used a soul-cutting sword to great effect. In the end, Rimuru narrowly escaped death by allowing a body double to take the final blow, and Hinata departed, convinced that she had just won. But for Rimuru, the worst was yet to come.
4 NEEDED AN ALLY: When He Fought Charybdis
At one point in Season 1, Rimuru and his allies beheld the titanic Charybdis, a flying monstrosity that seemed to be immune to all conventional attacks. Rimuru could barely even slow it down, but his new ally, Demon Lord Milim Nava, was eager to fight it and prove her worth to Rimuru.
Rimuru stepped aside and watched in awe as Milim soared into the sky and confronted Charybdis solo. She fired up her Drago Buster spell and blasted Charybdis into dust with it. And that wasn't even the full extent of her power - she could have done even more.
3 ACTED ALONE: When He Printed Manga Volumes For Yuuki
Sometimes, Rimuru acts alone because he is literally the only person who can accomplish a certain task, and the results can be quite amusing. Late in Season 1, Rimuru visited a human kingdom and met Yuuki Kagurazaka, unaware that Yuuki was actually his enemy. Also, Yuuki was an Otherworlder, just like Rimuru.
As a token of friendship, and to pay tribute to his and Yuuki's Japanese origins, Rimuru generously printed hundreds of manga magazines and volumes for Yuuki to read, for which Yuuki was grateful. No one else could just print books from their own body like that.
2 NEEDED AN ALLY: When He Met The Eurazania Delegates
Early in Season 2, Rimuru was building diplomatic ties with the Animal Kingdom of Eurazania, and he assembled a small group of representatives to meet the Eurazania delegates on neutral ground. The Eurazania delegates, led by the three Beastketeers, wanted to test Rimuru and his friends.
So, Suphia challenged Rimuru's group to a fight, and Shion volunteered to duel Suphia in a bare-handed fight. Similarly, the beastman Grucius clashed with Rimuru's human ally Youm, and it was Rimuru's job to merely watch and hope that his allies could win the day. And they did.
1 ACTED ALONE: When He Absorbed The Orc Disaster
Rimuru needed hundreds of allies on his side to fight the massive orc army, including Gabiru and his warriors, but the final blow was one for Rimuru to deal alone. The towering Orc Disaster was too big and strong for ordinary spells to work, so Rimuru used his Predator skill, something unique to him.
Everyone else watched tensely as Rimuru enveloped the Orc Disaster in his slime body, and the Orc Disaster resisted with its own immense power. In the end, though, Rimuru triumphed, and the Orc Disaster was no more. After that, a new orc leader was chosen, a humble and hardworking fellow named Geld.