When a God of Destruction Was Reincarnated in Tensura:

The day of Walpurgis had arrived, and Tempest was abuzz with preparation. Rimuru, looking sharp in the outfit crafted by Shuna, stood ready with his chosen subordinates: Zegion and Diablo. Zegion, the silent yet awe-inspiring protector of Tempest, stood with quiet confidence ( he did not fight during the war, Rimuru kept him hidden just in case), while Diablo radiated his usual mix of elegance and sinister loyalty.

Rimuru's Preparations

As the preparations were underway, Ramiris fluttered around Rimuru, acting as his impromptu guide for the upcoming meeting.

Rimuru: "So, Ramiris, what's the deal with the other Demon Lords? I know a little about some of them, but not all."

Ramiris (grinning): "Oh-ho! You're in for a treat, Rimuru! Let me tell you all about them! But first, remember, only two subordinates per Demon Lord. You sure about bringing Zegion and Diablo?"

Rimuru: "Absolutely. Diablo's been itching for this, and Zegion... well, let's just say he's my ace in the hole."

Ramiris nodded, impressed, before starting her detailed explanation of the Demon Lords.

Guy Crimson, the first and oldest Demon Lord.

Guy was born during the dawn of time, before the creation of heaven and earth. He was one of the demonic counterparts to the Seven Angels of Origin, having split from the Great Holy Spirit of Darkness. As the first among them to be born, he ruled the Daemon Realm as its king and commanded the daemons at will.

From his perspective, even the other primordials were mere dependents. However, when Bleu and Vert challenged him in a bid for supremacy, he easily defeated them but discovered that the primordials were immortal. No matter how crushed they were, they would resurrect under the victor's command. This realization led to a stalemate among the remaining four primordials.

Among the daemons, the Black Primordial Noir persistently troubled Guy. They fought for supremacy, resulting in a draw. Recognizing Noir's strength, Guy acknowledged him as a rival.

With the passage of time, Guy was summoned to the Central World by High human Emperor Jahil of the Super-Magic Empire. He was summoned as an archdaemon and tasked with destroying an enemy nation. Using a million corpses, Guy successfully incarnated and ascended to the rank of true demon lord, acquiring the souls of numerous people.

In addition to destroying the enemy nation, he summoned Primordial Vert and Blue, ordering them to slaughter Jahil and all the residents of the Super-Magic Empire while avoiding mass destruction magic to prolong their suffering.

As Guy crushed his enemies, he relished in their doomed pleas and found it to be a pleasant sound. He named himself Guy, after awakening as a True Demon Lord. He named his companions Misery and Rain, reflecting the misery of mankind and the rain of blood that fell wherever he went.

Guy and his maids traveled from place to place, enjoying the world. Eventually, he encountered Veldanava and challenged him to a fight but was easily defeated. Instead of becoming Veldanava's servant, he was given the role of Mediator.

Milim Nava – The Destroyer

Ramiris: "Speaking of Milim, she's next! Milim Nava, the Destroyer, is one of the most chaotic and unpredictable Demon Lords you'll ever meet."

Rimuru (nodding): "Oh Yeah."

Ramiris (laughing): "Of course you have! But there's more to Milim than meets the eye. She's the daughter of the True Dragon Veldanava, the creator of the world, and Lucia, a human who loved him. As a Dragonoid, she inherited some of her father's godlike powers. That's why she's so ridiculously strong—it's literally in her blood!"

Rimuru's expression softened.

Rimuru: "She's been through a lot, hasn't she?"

Ramiris (nodding solemnly): "She has. Milim lost her parents when she was young, and her beloved pet dragon was killed by humans. In her rage, she destroyed an entire country, earning her the title of the Destroyer. But deep down, Milim's just a lonely girl who wants friends. She's a lot smarter than people think, though. And don't forget, she's ridiculously loyal to those she cares about—"

Ramiris – The Fairy Demon Lord

Ramiris: "And then there's me! Ramiris, the Fairy Demon Lord! The most beautiful, brilliant, and lovable of all the Demon Lords!"

Rimuru (smirking): "A little humble brag, huh?"

Ramiris (puffing her chest): "It's not bragging if it's true! Anyway, I'm one of the oldest Demon Lords, too, though I've… uh… 'reset' a few times."

Rimuru (curious): "Reset?"

Ramiris (sighing): "Yeah, let's just say I have a knack for getting into trouble. I'm the guardian of the Spirit Realm and used to work alongside Veldanava to maintain balance in the world. But when Veldanava passed, things got messy, and I ended up becoming a Demon Lord to protect what's left of his legacy."

Rimuru could sense a hint of sadness beneath her playful tone but decided not to press further.

Luminous Valentine – Queen of Nightmares

Ramiris: "Next up is Luminous Valentine, also known as the Queen of Nightmares. She's a vampire and rules over the Holy Empire of Ruberios. Don't let the 'Holy Empire' name fool you—it's a vampire nation through and through."

Rimuru: "A vampire Demon Lord? Interesting."

Ramiris: "Very. Luminous is ancient, even older than Milim, though not quite as old as Guy. She's terrifyingly strong, but she hides it behind a calm and elegant exterior. Her subordinates are fanatically loyal to her, especially Hinata, the leader of the Ten Great Saints.

Rimuru then remembered with a grin on his face: "Oh that Hinata."

"Luminous is a bit of a mystery, but she's surprisingly fair when it comes to ruling her people. Just… don't cross her. She has no patience for betrayal."

Draguel - The Giant

A long time ago, in the age of myth, an evil giant emerged from the depths of the earth, wreaking havoc wherever it went. Eventually, Veldanava intervened and managed to defeat the giant, splitting it into three separate entities: Dagruel and his two brothers, Fenn and Glassord. Over time, Dagruel and Glassord renounced their malevolent ambitions and strived for redemption, while Fenn clung to his wicked ways and was subsequently sealed away. As a reward for his change of heart, Veldanava granted Dagruel a parcel of land and entrusted him with the duty of guarding the Heaven Tower to prevent Fenn's release.

Leon Cromwell - The Platinum Saber

He is the last born Demon Lord, the human "Demon Lord" Leon Cromwell. He with his overwhelming magical power rules over his increased number of Majin, he identifies himself as the Demon Lord of the frontier.

One of the Demon Lords was furious with him, the Demon Lord Kazaream had waged war against him. But he was beaten by Leon instead. It was also by Leon's own hands. Due to this, Leon's "Hero's egg" hatched and he awakened as a true hero. In response to the situation, the other Demon Lords, not knowing that Leon is a hero, recognized him as a new Demon Lord.

With the explanations done, Rimuru felt more prepared for Walpurgis.

Rimuru (grinning): "Thanks for the info, Ramiris. I think I'm ready for whatever happens."

Ramiris (teasing): "Don't get too cocky, slime! Walpurgis is a whole different ballgame."

Rimuru chuckled, knowing full well that the meeting was bound to be as chaotic as the Demon Lords themselves.