All Primordial Demons Ranked: How They Broke the Tensura Power System

If there’s one thing that makes That Time I Got Reincarnated as a Slime stand out from other isekai anime, it’s the absurdly layered power system.

Sure, plenty of series throw around overpowered characters, but Tensura does something different — it introduces beings that feel genuinely mythical. And no group represents that better than the Primordial Demons.

The moment the anime started teasing Diablo’s true identity, longtime Light Novel readers already knew the story was entering dangerous territory.

These aren’t ordinary demons. They are ancient manifestations of darkness itself, entities that existed long before kingdoms, Demon Lords, or even human civilization. In many ways, the Primordials are the hidden rulers of the Tensura world.

As a fan, I honestly think the Primordial Demons are one of the biggest reasons Tensura feels so addictive. Every single one of them has overwhelming presence, unique personalities, and powers that sound less like magic and more like reality hacks.

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Let’s break down all seven Primordial Demons, their origins, abilities, and why they completely changed the balance of the series forever.

What Are the Primordial Demons in Tensura?

The Primordials, often called the Seven Pillars, are the oldest and strongest demons in existence. They were born from the Great Holy Spirit of Darkness, making them fundamental spiritual beings rather than normal monsters.

Unlike weaker demons that evolve through combat or naming, the Primordials existed from the very beginning. Over countless ages, they fought endlessly in the Underworld, sharpening their strength to terrifying levels.

What makes them fascinating is that they aren’t just powerful — they each embody different philosophies and personalities. Some crave destruction, others seek entertainment, while a few simply follow whoever interests them most.

And somehow, Rimuru managed to recruit four of them.

That alone says everything about how ridiculous Tempest eventually becomes.

1. Guy Crimson — The Monster Even Demons Fear

There’s strong, and then there’s Guy Crimson.

Guy isn’t just the oldest Primordial — he’s basically the benchmark for demonic supremacy in Tensura. Even other monsters at True Dragon level treat him carefully.

What I love about Guy is that he never feels like a generic villain. He’s charismatic, calm, playful, and terrifying at the same time. One second he’s joking casually, and the next he’s casually discussing world-ending warfare like it’s a board game.

Why Guy Is So Dangerous

• Possesses the Ultimate Skill Lucifer
• Can reportedly copy abilities after seeing them
• Fought True Dragons evenly
• Acts as the unofficial balance keeper of the world

Unlike many overpowered anime characters, Guy doesn’t constantly flex his power. That restraint somehow makes him even scarier.

The craziest part? Most fans still debate whether current Rimuru has truly surpassed him.

2. Diablo — The Most Terrifying Loyal Servant in Anime

Diablo might honestly be my favorite character in all of Tensura.

At first glance, he acts polite, elegant, and weirdly respectful. But underneath that calm smile is probably the most mentally unstable Primordial in existence.

Before meeting Rimuru, Diablo, formerly Noir, had almost no interest in ruling territory or becoming stronger. He simply wanted stimulation and truth. Rimuru fascinated him enough to completely abandon his old existence.

And once Diablo becomes loyal, it’s over.

Why Fans Love Diablo

• Absolute devotion to Rimuru
• Unmatched intelligence
• Calm but horrifying personality
• Constantly hides his true strength

One detail I always found interesting is how Diablo intentionally limits himself for entertainment. Even his existence value being set around 6,666,666 feels perfectly in-character.

His Ultimate Skill Azazel is also absurdly broken, allowing him to manipulate perception and trap enemies in psychological nightmares where illusion and reality become impossible to separate.

Honestly, Diablo feels less like a demon and more like a cosmic horror disguised as a butler.

3. Testarossa — Elegance Mixed With Pure Cruelty

Testarossa is proof that Tensura understands how to write genuinely intimidating female characters.

She carries herself like a noblewoman, speaks calmly, and handles diplomacy better than almost anyone in Tempest. But behind that elegance is someone capable of massacring entire armies without hesitation.

The infamous Lake Shore Dyed Scarlet Incident alone made other nations terrified of her existence.

What Makes Testarossa Special

She doesn’t rely on brute force.

Instead, she weaponizes intelligence, manipulation, and precision. Her ability to instantly kill targets through advanced death magic makes her arguably the most efficient assassin among the Primordials.

Her Ultimate Skill Belial gives her terrifying authority over life and death itself.

In many ways, Testarossa feels like the perfect political weapon for Rimuru’s empire.

4. Carrera — The Walking Natural Disaster

Carrera is absolute chaos.

While the other Primordials often act refined or composed, Carrera feels like someone who genuinely enjoys seeing explosions just because they look cool.

And somehow, that makes her incredibly entertaining.

Among Rimuru’s subordinates, she arguably possesses the most ridiculous raw destructive power. Her attacks don’t just defeat enemies — they erase landscapes.

Carrera’s Biggest Strengths

• Massive mana reserves
• Catastrophic area attacks
• Loves combat
• Zero fear of collateral damage

Her signature techniques like Gravity Collapse and Abyss Core sound less like magic spells and more like forbidden weapons.

Once she obtains the Ultimate Skill Abaddon, her destructive capability jumps even further.

If Diablo is psychological terror, Carrera is straightforward apocalypse energy.

5. Ultima — The Scariest Smile in Tensura

Ultima might look harmless, but she’s honestly terrifying.

What makes her disturbing isn’t just her strength — it’s how much she enjoys suffering. She’s playful, cheerful, and completely sadistic underneath.

Tensura often balances comedy with darker themes, and Ultima represents that balance perfectly.

Why Ultima Is So Dangerous

• Master of poison abilities
• Expert at torture and intelligence gathering
• Extremely cunning
• Can bypass resistances with soul-targeting toxins

Her Ultimate Skill Samael specializes in poisons that affect not only the body, but the soul itself.

That’s horrifying even by Tensura standards.

And somehow, she still manages to be weirdly lovable as a character.

6. Misery — The Silent Backbone of Guy Crimson’s Empire

Misery doesn’t receive as much spotlight as Diablo or the Demoness Trio, but underestimating her would be a massive mistake.

She represents something important in Tensura: true power doesn’t always need dramatic scenes.

While Guy dominates through overwhelming charisma and combat ability, Misery handles logistics, structure, and stability behind the scenes.

Misery’s Role

• Oversees Guy’s territory
• Specializes in support magic
• Extremely disciplined
• Acts as Guy’s trusted aide

Compared to the louder Primordials, Misery feels more grounded and mature.

That calmness actually makes her feel more believable as an ancient demon who survived countless eras.

7. Rain — The Most Underrated Primordial

Rain is probably the Primordial fans underestimate the most.

She’s sarcastic, lazy, artistic, and constantly annoyed by Guy’s behavior. Compared to the others, she feels surprisingly relatable.

But that’s exactly why she stands out.

What Makes Rain Interesting

• Highly skilled with magic control
• Uses mist and ice abilities
• More expressive than Misery
• Secretly extremely talented

I actually enjoy Rain because she adds personality balance to the group. Without characters like her, the Primordials could feel too overwhelmingly serious all the time.

She makes the group feel more alive.

Why the Primordial Demons Changed Tensura Forever

Before the Primordials became central to the story, Tensura already had powerful characters. But once these ancient demons entered the spotlight, the scale of the series exploded.

Rimuru naming Diablo, Testarossa, Carrera, and Ultima wasn’t just a flex — it completely shattered the global balance of power.

Suddenly, Tempest possessed multiple beings capable of rivaling entire nations by themselves.

And honestly? That’s when Tensura became truly insane in the best possible way.

The Primordials aren’t memorable just because they’re strong. They’re memorable because every single one feels unique. Different motivations, personalities, combat styles, and philosophies make them feel like real legendary beings instead of generic overpowered villains.

For many fans, they represent the peak of Tensura storytelling.

And with future anime seasons diving deeper into their roles, anime-only viewers still haven’t seen the craziest moments yet.