Diablo

""Hee-hee-hee-hee-hee.The birth of a new demon lord! Quite an old sensation but a familiar one.What a truly wonderful day ! Such a offering-and the very first order from our lord, no less.This is such an honor; I couldn't possibly be more enthusiastic about this.Would it be all right to continue serving you in the future?"."

- Diablo

Diablo (ディアブロ), also known as Noir (原初の黒) is one of the seven Demon Primordials and an Executive of the Jura Tempest Federation as the second Secretary of Rimuru Tempest.

Arch Demon


Black hair with streaks of red and gold, as well as golden eyes, Noir was finely dressed in garments like that of a prince. Other than that he looked like a normal human, though he was able to unfold wings as well.

Demon Peer
Diablo's change in appearance is possibly the least drastic after any evolution, only his princely garments were replaced by a Butler outfit, reflecting his wish to serve Rimuru, but despite that, his dignity didn't decrease, but rather even increased.

Personality
Diablo is whimsical but also very calculative when he wants to be. He usually shows an absolutely composed attitude, but whenever anyone insults Rimuru, his polite exterior turns into a cold form of malice and he proceeds to punish the "sinner" in the most painful way imaginable unless it goes against Rimuru's orders. However when someone has a good relationship with Rimuru, Diablo usually treats them amiable, though he might still manipulate them for his own ends, with "his own ends" usually referring to being close to Rimuru more often.

Diablo follows Rimuru's orders to the letter. When tasked with increasing the difficulty of Flamaire's test as a guard for guests to Tempest, Diablo summoned a moderately strong monster. The moment Flamaire got paralyzed by the creature's goo and still showed a will to fight, Diablo sent the creature away and went to report back on Flamaire's actions. Should there be some "grey area" in his instructions, Diablo has the freedom to carry out his orders how he sees fit.

The greatest show of Diablo's loyalty to Rimuru was recruiting hundreds of other demons (including the last three progenitors) to serve his master; the creation of the Black Numbers, who became the de facto strongest fighting force in Tempest.

Backstory
Thought of as strange by the other Primordials, Noir only acted on whims and didn't show any regular behavior, to the irritation of some of the other Primordials. Due to that he one day stopped pursuing power as his power efficiency became so high that any fights were too easy for him, causing him to remain as an Arch Demon despite having enough power to evolve into a Demon Peer already.

One day when he personally answered a Demon Summon of a Silver Wing on a whim, he had a chance encounter with Shizue Izawa. During a confrontation, where Noir was about to finish her off, he was repelled by Shizue's Anti-Magic Mask instead, making Noir realize that the mask can has the power to surpass time or the power of infinity. After those events, he returned to the Spiritual World and ​​​​​​​continued observing Shizue and the mask in secret. When he saw that the mask broke and lost its power when the mask came into Rimuru's hands, Noir came to the conclusion that Rimuru is connected to that power of the mask that surpasses time itself as he witnessed and that Rimuru is, therefore, the key to the "truth of the world."

He tried to get summoned by Rimuru when Rimuru made a Greater demon summoning within Ramiris Labyrinth, but he failed and Beretta of his own line of Demons, answered the Summon first, to Noir's chagrin.

Finally, when Rimuru did another Greater demon summoning to catch the hiding Razen, Noir managed to answer the call alongside two of his Greater Demon followers. After some further events, Noir finally received the Name "Diablo" from Rimuru and evolved into a Demon peer

Noir v/s Shizue Izawa - Retreat
One day when he personally answered a Demon Summon of a Silver Wing on a whim, he had a chance encounter with Shizue Izawa. Shizue figured out that something was wrong with the man in robes and that he had the plan to kill everyone in the castle just for finding a demon. This caused Noir and Shizue to battle.Noir seemed to playing around with Shizue during the battle but in the end Noir got somewhat of a severe injury from Shizue's Anti-Magic mask and had to retreat.

Noir v/s Named Arch-demon - Victory
The demon guided Shizue Izawa to a trap to kill Shizue, she was exhausted from her fight with Noir and couldn't put much of a fight against the Arch-demon and as she was going to let Ifrit rampage as a last desperate attempt but Noir showed up and proceeded to kill the demon easily.

Noir v/s Razen - Victory
Rimuru did a Greater demon summoning during his harvest festival as he was going to sleep.By offering the soul-less corpses of the 20,000 Farmus soldiers, Rimuru successfully summoned Noir and his two Greater Daemon subordinates. Using the corpses, they were able to successfully materialize and Rimuru's first order for them was to capture the hiding Razen and bring him to Ranga. Mesmerized by Rimuru's Soul the three Daemons did their work promptly, successfully capturing Razen alive.

Diablo v/s Demon slayers - Victory
Damrada left Edward with a few demon slayers from the eastern empire to subjugate the demon (diablo) and these demon slayers eventually fought with Diablo. The fight was a overwhelming victory for Diablo but he didn't hurt much or kill any of them due to Rimuru's order and Diablo made them lose their will to fight. The demon slayers knew about the dangers of Diablo and were frightened to realize his true identity as a primordial demon and they surrendered.

Diablo v/s Sare and Glenda - Victory
Sare confronted Diablo and asked him about his true nature and identity, when Diablo revealed that he was a Demon peer , Sare got frightened and lost his will to fight realizing he could never against Diablo

Demon Lord Awakening
By offering the soul-less corpses of the 20,000 Farmus soldiers, Rimuru successfully summoned Noir and his two Greater Daemon subordinates. Using the corpses, they were able to successfully materialize and Rimuru's first order for them was to capture the hiding Razen and bring him to Ranga. Mesmerized by Rimuru's Soul the three Daemons did their work promptly, successfully capturing Razen alive.

When the secret revival art was lacking the necessary energy, Noir offered to sacrifice his subordinates, stating that they were delighted to be of use to Rimuru. Hence, when Rimuru awakened and found out that the Arch Daemon he summoned did his job properly he was grateful for his efforts and allowed Noir to become one of his vassals. When Rimuru found out that the Arch Daemon didn't have a name, he named him "Diablo." After Diablo was named, a black cocoon enveloped his body and the now named Diablo evolved into a Daemon Lord.

Afterwards, Diablo was allowed to attend the meeting to discuss their future plans.

The Octagram Soars Brightly
Diablo was then given the task of investigating Farmus and cripple its economy and overthrow the current Farmas king.

Trivia

 * Rimuru named Diablo after the Supercar.
 * Diablo's naming took half of Rimuru's total magicules reserves even though his total magicule capacity increased by ten times after becoming a demon lord.
 * Diablo is Rimuru's strongest named subordinate.
 * Diablo's happiest thing to do is butler/housekeeping work for Rimuru.
 * Diablo is a loner who doesn't like having subordinates unless it is for the sake of his master.