A Dire Wolf that evolves into a Tempest Wolf after being named by Rimuru and later still into a Tempest Star Wolf. He and his pack became Rimuru's followers after he killed his father, holding no grudge against him.
- Bash Brothers: Well, Bash Brother and Sister in this case, but he and Shion team up against Charybdis when the giant monster attacks.
- Big, Friendly Dog: After evolving. This becomes especially pronounced whenever he's in his true form, which is so big, it can hardly fit into the classroom of the Summoned Children.
- Black Eyes of Crazy: Averted. The sclera in Ranga's eyes is completely black, and yet he's among the most noble members of Tempest.
- Blow You Away: Receiving a name evolved him to a Tempest Wolf, giving him power over wind.
- Defeat Means Friendship: After his father is killed, he and his pack swear complete allegiance to Rimuru.
- Does Not Know His Own Strength: At first, he had trouble controlling the whirlwinds he causes with his tail.
- Evolution Power-Up: Evolves into a Tempest Wolf after being named by Rimuru, then later still evolves into a Tempest Star Wolf during the battle with the Orc Lord's army.
- Gentle Giant: Ranga's true form towers over quite a few characters, but as long as they're on Rimuru's good side, he's easily one of the most affection wolves you'll ever meet.
- Hive Mind: How he explains the reason why naming only him was enough to evolve all of the direwolves. According to him, they share one mind, and so by naming him, the current leader, the other wolves got to evolve as well.
- Know When to Fold 'Em: Once his father is killed, and Rimuru uses his newly acquired "Intimidation" skill on him, he's the first to surrender to Rimuru's authority, with the rest of the direwolves surrendering soon after.
- Loyal Animal Companion: Becomes one to Rimuru, acting more or less like his pet, and always by his side or hidden in his shadow.
- Noble Wolf: Unlike his overconfident father, he is friendly and very loyal.
- Shadow Walker: Ranga and all the Tempest Wolves have the "Shadow Movement" skill allowing them to hide and appear from shadows even a great distance away.
- Shock and Awe: He can shoot lighting strikes from his horns.
- Size Shifter: He develops the ability to change his size after Rimuru gives him a name; he starts out massive, but later shrinks to merely larger than average for a wolf for practicality.
- Supernatural Gold Eyes: His pupils are golden, and both his fur color, star-shaped mark, and abilities after evolving make it quite clear that Ranga's quite supernatural compared to his fellow Tempest Wolves.
- Turn the Other Cheek: Rimuru directly asks him about how he feels about the fact that Rimuru killed his father. Ranga admits that he still thinks about it but is much more grateful towards Rimuru for sparing the rest of the Dire Wolves when he had them at his mercy and then granting them a clan name, evolving them into Tempest Wolves. Rather than be resentful, he'd much rather show his thanks through his clan's Undying Loyalty.
- Weather Manipulation: During the battle with the Orcs, he uses the wide-range attack "Death Storm", which creates massive twisters all over the battlefield coupled with lightning bolts powerful enough to kill an Orc General with one shot.
- You Killed My Father: Subverted towards Rimuru, see Turn the Other Cheek above.
Lizardmen / Dragonewts
The son of the Lizardmen Tribe chieftain and the self-proclaimed hero of his nation. Incredibly arrogant and haughty, he gets his comeuppance quite rapidly, after which he follows the same Defeat Means Friendship dynamics with Tempest.
- "Ass" in Ambassador: He spends his first meeting with Rimuru's village constantly insulting Rimuru for being a slime and treating his followers as if they were pathetic weaklings. It's just a few sentences in before Benimaru is asking Rimuru for permission to kill him. The ironic thing is that Gabiru was supposed to be there to ask for their help.
- Blade on a Stick: His main weapon is a spear, and he obtains his father's Vortex Spear.
- Boisterous Weakling: Well, he's not exactly weak but more undisciplined and completely unused to actual combat against enemies that can match his strength. When he's pitted against Gobta by Rimuru he makes a big show of his attacks instead of being cautious and winds up getting caught completely off guard by Gobta knowing the "Shadow Movement" skill. He fares better against the Orc General due to realizing he can't afford to hold back anything, but even with his father's Vortex Spear he can barely stand his ground, much less actually win.
- Defeat Means Friendship: Joins Rimuru after the Orc Lord is defeated and he himself is banished for his (admittedly well-intentioned) treason against the Lizardmen.
- Draconic Humanoid: Is a Lizardmen.
- Dragon Ancestry: Lizardmen claim to be descended from dragons.
- Face Death with Dignity:
- With the Orc General's ax bearing down on him and no time nor energy to react, instead of panicking, he simply closes his eyes and calmly awaits his inevitable end. Luckily The Cavalry shows up at that exact moment.
- When he believes his father intends to kill him for his treason, he not only fully accepts the punishment, but even considers it is only right for what he did.
- A Father to His Men: He refuses to let his subordinates join him in fighting the Orc General due to the difference in power, and he's reduced to tears when they throw themselves in front of him to save him from Gelmud's magic attack. When Rimuru throws him healing potions, he scrambles as fast as he can to use them on his downed comrades, and this act of selflessness is what makes Rimuru's opinions of him become much more favorable.
- Fearless Fool: About the only positive thing about Gabiru Rimuru can get from his initial impressions is that he's incredibly brave, as shown when he's the only Lizardman not cowering in fear before an angry Ranga at his full size. Combined with his ego, however, it just makes him all too willing in jumping into situations without thinking.
- Foolish Sibling, Responsible Sibling: He more or less plays the Foolish Sibling to Souka's Responsible Sibling. While Gabiru was off doing whatever upon being named, and in general being way too full of himself, Souka was doing her job as the captain of the guard, keeping her father and her people safe.
- Heroic BSoD: He hits his when he learns straight from Gelmud's mouth that in the end he was just an Unwitting Pawn meant to be eaten by the Orc Lord in order to fuel his ascent to Demon Lord, and it only gets worse when those amongst his admirers throw themselves in front of Gelmud's attack to save him and nearly die. He's reduced to crying by the end as Rimuru hands him healing potions that he desperately uses on his men as fast as he can.
- A Hero to His Hometown: Other members of the Lizardman Tribe love this guy, mostly because of the prestige that actually having a name provides. Unfortunately, this has the side effect of stoking his ego, preventing him from really worrying about improving himself and making him seem pompous and irritating to outsiders.
- Hidden Depths: Deep down he questions his own hype and does seem to genuinely want to make sure his father can retire with peace of mind. He is also surprisingly not a terrible tactician, and knows how to plan battles in such a way as to exploit the Lizardmen's advantages over the Orcs in their native terrain, though his plans fail because he went into battle without bothering to learn anything about his enemy.
- Normal Fish in a Tiny Pond:
- Played straight before Rimuru's appearance, as he does have all the advantages he brags about when compared to the average Jura Forest inhabitant who were mainly low-level monsters like goblins or kept to themselves like dryads.
- Inverted after Rimuru appeared and started his nation-building quest. Gabiru is near-worshipped by his fellow lizardmen and is special among them due to having a name and having all the benefits it provides. However, when compared to those who follow Rimuru, who takes it upon himself to give everyone under him a name and on top of being stronger than the one who gave Gabiru his, he's just a nobody with an overinflated opinion of himself.
- Oh, Crap!: He has one when he senses the power of a large Orc and assumes it's the Orc Lord. It only gets worse when the orc reveals it's "just" an Orc General and far inferior to the true Orc Lord, and it reaches its zenith when despite giving a good fight he can't defeat it.
- Power Gives You Wings: After receiving a powerboost from being renamed by Rimuru, he grows a pair of wings.
- Purple Is Powerful: After receiving his powerboost and evolution from being named by Rimuru, his green skin turns purple.
- Small Name, Big Ego: A zig-zagging example. He does have an inflated sense of self-worth about being the Lizardmen Chieftain's son and possessing a name, but there are multiple points where he honestly questions if he's hyping himself up too much or that he's not good enough. His lizardmen comrades, on the other hand, are all too willing to stroke his ego to keep him going even further and burying his doubts.
- Took a Level in Badass: Accidentally gets named by Rimuru who states out loud that his current name is fine, granting him wings and a major boost in power. Believe it or not, he eventually becomes one of the 12 entities serving under Rimuru considered strong enough to be individual Demon Lords.
- Unwitting Pawn: Gelmud plays on his ego and desire to protect his people to make him overthrow his father and take control of the Lizardmen, relying on Gabiru's lack of knowledge about the Orc Lord's abilities to make him commit to a direct assault against the Orcs and get them wiped out to feed the Orc Lord's strength.
- "Well Done, Son!" Guy: The light novels say his secret motivation is to gain his father's approval, even when overthrowing him.
- Well-Intentioned Extremist: His desire to protect his people from the Orcs drives him to betray his father and chieftain to seize power over the Lizardmen, which in and of itself is a ploy by the demon Gelmud and his comrades to slaughter the Lizardmen.
A group of Lizardmen who are fantastically devoted to Gabiru, and who answer to his beck and call.
- Nice Job Breaking It, Hero!: See Small Name, Big Ego in Gabiru's folder.
- Satellite Character: An entire group of them for Gabiru.
- Taking the Bullet: When Gelmud attempts to murder Gabiru, they willingly throw themselves in front of his attack to save their idol. They would have most likely died had Rimuru not given Gabiru some healing potions to save them.
- Undying Loyalty: To Gabiru. When he's practically exiled from the clan, they meet with him and reveal they've volunteered to join him in exile to be with him.
The younger sister of Gabiru, and the former captain of the guard. She left her clan in order to join Tempest so she could further enhance her skills, an order given by her father.
- Action Girl: She's the captain of the guard for a reason. This becomes especially more prominent after being named.
- Bishōnen Line: Sure, every monster goes through this after being named, but it's notable with Souka and her aides because they go from clearly lizardlike humanoids, to essentially humans with draconic wings, horns, and notable fangs. The change is even more notable when compared to Gabiru and his men, who merely gain a power boost and wings.
- Cute Little Fangs: These, alongside her draconic traits, are the only things separating her from humans after being named.
- Cute Monster Girl: Even before evolving from being named, Souka had a notably softer look compared to the rest of the lizardmen.
- Daddy's Girl: It's subtle, but Souka seems to hold a great affection for her father: She stayed by his side during the Orc trouble, she's the one to help him stand up after rescuing him after Gabiru's betrayal, and when she
- The Dutiful Son: She acted as this during her time as the captain of the guard, helping protect the temple
- Ninja: As a member of Souei's the Shadow Squad, she dresses like a stereotypical anime ninja and practises the same stereotypical anime ninja tropes that Souei does.
- Number Two: She becomes Souei's second-in-command of the Shadow Squad.
- Winged Humanoid: Once she becomes a Dragonewt, she resembles a human woman — though she can sprout draconic traits like horns, wings, and a tail at will.
- The Apprentice: Along with Souka, to Souei.
- Winged Humanoid: Same deal as Souka.
A race of boar-like humanoids who were once controlled by the Orc Disaster. They were actually a tribe of Orcs who were suffering through a great famine, and most of them were brainwashed by the effects of Starved into trying to devour everything and everyone to satiate their hunger. Once everything is cleared up and the effects of Starved are gone, the Orcs become part of Tempest's workforce.
- Cannibalism Superpower: Under the influence of Starved, they could assimilate traits from other monsters they devoured — like obtaining scales and webbed toes from eating Lizardmen.
- HeelFace Turn: Once the effects of Starved are over and they're allowed to live in Tempest, they swear loyalty to Rimuru and become the main construction force of the city.
- Infant Immortality: Nope, even the children who weren't lucky enough to get food for the famine wound up hitting the dirt bed.
- Villainous Glutton: Back when they were under the effects of Starved, they would devour anything and anyone they came across, including their own dead, to become more powerful.
The former aide to the Orc King, who then became an Orc Disaster to try and prevent a famine. He was one of the survivors of the attack against the Starved Orcs, and was later named by Rimuru to carry the legacy of the good king.
- The Atoner: He desperately wants to make up for the transgressions of the Orcs, even knowing it was a Deal with the Devil situation with no good ways to end.
- Legacy Character: Named after the very Orc Disaster he once served, so that he could carry on his legacy.
- Workaholic: Geld has a very bad habit of working past his limits.
The head dryad of the Jura Forest, and one of the most powerful allies Tempest has in the early part of the story, as the dryads have the power over the forest itself. She asks Rimuru to deal with the orcs, seeing them as a threat to the forest and its inhabitants in general.
- Big Eater: She helps herself to the food at the banquet, and as noted by Kaijin, she certainly can eat a lot.
- Does Not Like Shoes: She is shown to not wear any shows under her skirt in certain frames.
- Eyes Always Closed: She's usually depicted with her eyes closed. Them being open is usually a sign she's either angry and ready to fight, or being serious about something.
- Green Thumb: She's a dryad, so it's kind of a given that she'd be able to control plants.
- Nature Spirit: As a dryad, she is a female Plant Person; and was in charge of Jura Forest before designating Rimuru the king of the monsters there.
- Plant Person: A dryad.
- You Gotta Have Blue Hair: She has green hair.
An ancient and powerful archdevil known as the Black Progenitor, who was summoned by Rimuru during his ascension to Demon Lord. Named Diablo, he evolved into a Demon Duke; and worships Rimuru as a god.
- Adaptation Dye-Job: In the original web novel he has solid red hair, but in the light novel and subsequent adaptations he has black hair with red and yellow streaks.
- An Arm and a Leg: He lost an arm when he tried to slash through Shizu's anti-demon mask, though she noted he was holding back.
- Battle Butler: He is employed as a butler and leads the Black Numbers — a corps of demon butlers and maids.
- Bishōnen: Upon manifesting, he assumes the form of a beautiful, androgynous man.
- Black Eyes of Crazy: His bloodthirsty demonic nature is highlighted by eyes, which have black sclera with red markings and yellow irises.
- Blood Knight: His love of elegance and gracefulness aside, Diablo really likes fighting, and before being summoned and named by Rimuru he was often bored out of his mind by the fact he rarely got to face off against opponents worth his time. Part of the reason he answered Rimuru's summonings was specifically because Rimuru is strong, surrounded by powerful subordinates, and often fights powerful foes.
- Deal with the Devil: What he would do to pass the time while bored before being summoned by Rimuru. In exchange for his summoner's soul, he would destroy their enemies utterly.
- Demon Lords and Archdevils: He was originally a nameless Archdevil, before evolving into a Demon Duke upon being named and eventually becoming a Demon God. He also holds the title of Demon Lord thanks to Rimuru upgrading him.
- Everyone Calls Him "Barkeep": Before he was named, he was simply referred to by others by his signature color — Noir/Kuro/Black.
- Expy: Rimuru making him a butler was a nod to Sebastian Michaelis from Black Butler.
- Hunter of His Own Kind: In the past, Diablo was summoned by one of the members of a team of heroes called the Silver Knights in order to avenge them. Their killer was the archdemon Orthos, who was powerful enough to defeat Shizu — albeit only after she was weakened by a duel with Kuro. After mopping up the lesser demons serving Orthos, the Black Progenitor rescued Shizu and utterly destroyed Orthos with ease — despite technically being of the same rank as Orthos, without a name of his own, and missing an arm.
- Multicolored Hair: While he had solid red hair in the original web-novel; in the light novel, manga, and anime he has black hair with red and yellow streaks.
- The Rival: To Shion, who he competes with for the position of Rimuru's number-one aide.
- Slasher Smile: When summoned by one of the members of Silver Knights to take revenge on the archdemon that mortally-wounded her and killed her partner, he sports a bloodthirsty grin while saying he'll reap her enemies to make up the rest of what he's owed.
- Voluntary Shapeshifting: He can form bat wings out of his back and turn his hands into extendable Wolverine Claws.
One of the Four True Dragons and the first intelligent being Rimuru meets after being reincarnated, he's the one who named him. He in turn received his last name from Rimuru. He had been sealed in a cave for three centuries when he met Rimuru, becoming his first friend.
- Badass Baritone: In the dub.
- Blood Knight: While not malicious, he needs to cut loose every once in a while. This is one of the reasons for his sealment.
- Destructive Savior: Near the end of the story he tries to make an apology of sorts to Ruminas for blowing up her kingdom that one time only to destroy it again first through collateral damage and then accidentally turning the entire place into a forest.
- Dramatically Missing the Point: His perspective is given focus at the ends of volumes and, while he learns compassion and patience from Rimura's memories, he still appreciates his actions from the perspective of an immortal unassailable dragon and not a humble mortal not fully aware or invested in their own power. In this way, he rationalizes Rimura's actions and luck as shrewd prudence and not the serendipity it is.
- The Dreaded: Very much so. He was indirectly responsible for the peace within Jura Forest due to his sheer presence alone. However, his disappearance sparks a war for territorial control between the monster races, at least until Rimuru arrives.
- Hidden Depths: His POV sidestory reveals he's picked up Shogi and gives Ifrit a handicap.
- Immortal Immaturity: Despite being one of the most ancient and powerful beings in the world, mentally Veldora is basically a somewhat bratty, self-centered teenager, full of petty impulses and uncontrolled whims, with Rimuru actually being a more mature and responsible part of their friendship.
- Immortal Procreation Clause: He implies he can breed but doesn't bother because living forever means he doesn't need to leave descendants. He says most magic born creatures think like that. Milim is also a good example as to why it would be a bad idea: When dragons reproduce, their power is almost entirely absorbed by their offspring. And assuming Rimuru is Veldanava, it took one hell of a long time to reincarnate compared to normal, if he did at all.
- Implausible Deniability: He mentions that he destroyed a vampires' city out of pettiness, and then pretended he had nothing to do with it. Understandably, no one believed him.
- Intergenerational Friendship: When they first met, Veldora was hundreds, if not thousands years old, and Rimuru was just 37 (or about 1 week as a slime). Ironically, he turned out much more mature than Veldora.
- Large Ham: As expected from a dragon, he's bombastic and loud whenever he's excited.
- Really 700 Years Old: He's practically ageless and has lived for centuries already. The three hundred years he's spent sealed up has him more worried that it'll kill him through the draining of his magic power than actually through old age.
- Sealed Evil in a Can: He was sealed by the Hero for blowing too much stuff up, basically. He's not exactly malicious but he basically gets bored and goes on rampages every now and then. After being unsealed he contains himself by reading manga, griefing newbies inside the labyrinth and eating cake.
- Ship Tease: He gets very familiar with Ifrit while they're both trapped within Rimuru. In the manga he thinks about giving him a woman's body with breasts to explore their appeal and in the anime spends an awkward amount of time holding his hand because he's warm.
- Smug Super: He is an immortal among the four strongest beings on the planet and is exactly as arrogant as that would imply. He mostly grows out of it.
- Tsundere: He's even called one by Rimuru when he denies something.
- Unskilled, but Strong: Before his imprisonment, he just tended to throw his power around carelessly. His two elder sisters are actually weaker, but Velzard would always kick his ass because she had much better control of her abilities. Thanks to the influence of Rimuru's manga and the wisdom of the people around him, however, he starts seeing the value of concentrated strikes, holding back his immense power and using actual techniques. By the end of the web novel, while Velzard is still generally considered to be the strongest dragon, he's improved at least enough to completely hand Velgrynd and titan Dagruel their asses, indicating that if he keeps it up he'll probably surpass Velzard as well.