Summary
One of the standout entries into the isekai genre,That Time I Got Reincarnated as a Slimetakes viewers on a journeyalongside Rimuru Tempest, the reincarnation of Satoru Mikami, a romantically despondent corporate worker who gets stabbed in the streets. He wakes up as an amorphous entity later named by Veldora as Rimuru Tempest.
Rimuru meets several individuals in this world who are as diverse as they come. From Majins to Orc Kings and Demon Lords, these characters come with varying levels of strength, but each possesses unique traits and skills that make it tough but not impossible to categorize them according to strength. Here are the ten strongest characters inThat Time I Got Reincarnated as a Slime.
This ranking is based purely on the anime series and not the light novels.
Updated July 17, 2025, by Emedo Destiny:With the release of its third season upon us,That Time I Got Reincarnated As a Slimehas done more than enough to earn its place as one of the best isekai of the last decade. The series follows the adventures of the slime called Rimuru Tempest after being reincarnated into the Central world from Earth as a human named Satoru Mikami. Thoroughly familiarising himself with his new world, Rimuru’s journey of survival and establishment brings him in contact with varying beings and species, some of which are the most powerful beings of the realm, like the dragon Veldora, among others ranging from high orcs to demon lords. So, accordingly, here are some of the series' most powerful characters in terms of strength.
15Adalmann
Species: Death Spirit
Formerly one of Clayman’s Index Finger of the Five Fingers, Adalmann is an undead now in service to Rimuru Tempest and the guardian of the 70th floor of the dungeon and is one of Rimuru’s Twelve Guardian Lords.
As one of the Twelve Guardians Lords, Adalmann is an extremely powerful lich capable of using holy and demonic magic in conjunction withhis necromancy abilitiesas an undead. As a previous devout follower of the Luminous faith, Adalmann possesses fanaticism, shown in his immovable display of faith loyalty in Rimuru. Even among the Guardian Lords, Adalmann ranks fairly, as he is a special S-Rank monster.
14Berreta
Species: Chaos Metalloid
Once a Greater Daemon, Beretta is a bodyguard of Rimuru, whom he summoned to inhabit a golem creation of his own. Upon her summoning, Beretta evolved into an Arch Doll, granting even more powers as she became Rimuru’s guardian entity. As a gesture to Ramiris by Rimuru, Beretta becomes Ramiris' permanent guardian at the latter’s behest.
As a Greater Daemon, Beretta was at least an A-Rank entity, implying she possesses incredible power. Her evolution into an Arch Doll signified increased strength, making her more powerful than a sky dragon and evolving further into a Special A-Rank monster. As a Chaos Doll, Beretta possesses a Chaos Core, putting her on par with a demon lord seed and now an S-Rank monster.
13Shion
Species: Divine Fighter
Rimuru’s first-ever secretary, Shion, is one of the executives of the upper echelon of the Jura Tempest Federation. Among the Twelve Guardian Lords, Shion commands her army, known as the ‘Yomigaeri.’ Formerly an Ogre, Shion evolved through the help of Rimuru into a Kijin and then into an Oni, leading to massive differences in power and physical traits.
Shion is a specialist at close combat and an immensely powerful melee fighter characterised by her impressive brute strength and swordsmanship. Capable of the ultimate skills called the Susanoo and Lord of Tyranny, Shion is easily above a sky dragon and on par with Beretta, making her a special S-Rank monster.
12Geld
Species: Divine Boar
Geld stands out among Rimuru’s followers as one of the strongest, especially as the Orc King. Now filling the position onceheld by his father, Geld’s power is comparable to the former Orc King.
Although certainly not the strongest of Rimuru’s subordinates, his physical strength and size are intimidating enough. With extra skills like being able to enhance his strength, use the earth as a tool, and manipulate his opponent’s actions through their thoughts, Geld is strong enough to wipe out a whole town or village.
11Hakurou
Species: Oni
Hakurou was strong even before Rimuru named him, but Rimuru certainly had an effect on him, making him stronger in several ways. He is strong andgreat with a sword, and his ability to keep his body temperature and presence under control is one of his great skills.
He gained an increase in the speed of his thoughts, making him perceive things in battle faster and more easily. Although Hakurou has undeniable strength, he relies heavily on his skill with a sword as it gives him an edge.
10Benimaru
Species: Divine Oni
As a Majin serving Rimuru, Benimaru’s strength is a given. He stands out even among the Twelve Guardian Lords. He’s just like Hakurou, possessing an enviable swordsmanship skill. His ability means he’s well-equipped for his role as the Jura Tempest Federation’s Minister of Defense.
Benimaru’spersonality may not matchhis ability, but it’s clear from the way he carries himself that he knows how capable he is. He’s also proud enough to avoid engaging those he considers to be beneath his level in strength, skills, and fighting ability.
9Hinata Sakaguchi
Species: Divine Human
Hinata Sakaguchi may owe her weapon, the Moonlight Rapier, to Luminous Valentine, who is stronger than she is, but Hinata can certainly handle her own in a battle. She loves to fight with rapiers, and her Moonlight Rapier inflicts wounds that are notoriously hard to treat.
Because of her strength, she is the most powerful in the church. With the Usurper ability, she can take power from those stronger than she is, making them weaker and easier to beat. With her skill called Mathematician, she can even predict the future.
8Carrion
Species: Divine Beast
Carrion is also called the Beast Master because he heads the Beast Kingdom Eurazania. As an aide to Milim Nava, strength and courage are important to him. But he also knows how to avoid a battle when he sees that the odds are stacked against him.
His Beast Roar shoots magic like a canon with incredible speed, and its power was enough to affect Milim Nava. Carrion also developed the Burst Roar using the Beast Roar as a base. With the Burst Roar, he basically uses his body as a weapon.
7Diablo
Species: Daemon
Diablo is Rimuru’s secretary and butler, and one of his most powerful followers. He is cool-headed and mischievous, but quick to turn into a menacing presence if Rimuru is affected in any way.
Diablo’s ultimate skill, the Azazel, unites his other skills called Tempter and Seeker. It includes a combination of several abilities, like accelerating his thoughts, using Demon Lord’s Haki to make an opponent go insane, or buildingthe ultimate barrierto protect from emissions or other physical and elemental attacks, with a chance to customize the barrier to suit any threat.
6Luminous Valentine
Species: Vampire
The Fifth seat at the Octagram, Luminous Valentine is a demon lord and ruler of all vampires and the True Ruler of the Holy Empire of Ruberios. As one of the oldest demon lords, she is mighty.
Typical of a demon lord, Luminous isan arrogant individualwho revels in her superiority to other species. However, Luminous is rather fond of her friendships with Chloe and Hinata, which were forged through harrowing years of establishing Ruberios as her domain after the destruction of Night Rose by Veldora. As a Demon Lord, she is capable of an Ultimate Skill as required and immensely proficient at using Holy magic, making her a special S-Rank monster.
