Even if Lord Momonga didn't forbid him from using Tempest citizens for experimentation, Demiurge would not have done so. The idea of harming anyone in his master's service was simply unthinkable.
Purposely causing a conflict to gain fresh test subjects was not an option either. The current political course was set to one of caution and defense, and making any sort of provocation would go against the direct orders of the Supreme Beings.
But for someone as crafty as him, restrictions only increased the desire to succeed in his endeavors. This is where summoning magic came in. Out of three options, elementals, demons, and otherworlders, only the latter two would provide suitable test subjects.
With otherworlder summoning taking too much time, Demiurge decided to stick to demon summoning. In such a way, he wouldn't need to waste demons connected to his skills and at the same time experiment with demons summoned with local magic would differ from Yggdrasil demon summoning.
As someone with common sense, he, of course, did the research beforehand and compared Nazarick's summoning magic to one that was commonly used in this world. Acquiring such knowledge was child's play, since the humans, as a lesser species, could not bother to put proper protection around their library in Blumund's royal castle.
A single specter was all that Demiurge needed to copy all the knowledge found there.
For most, this knowledge was subpar, to say the least, but on the upside, it gave great insight into how humans used magic. Unlike the monsters who relied on innate reserves, human mages had to gather magicules from the air. Otherworlders in that sense were essentially monsters that looked fully human.
When it came to summoning magic the result was the same. Monsters mostly summoned weaker creatures and befriended or enslaved them, while humans had to either pay a price or hope the summoned spirit would want to befriend them. The fact that they had to form pacts with summoned demons, often paying dearly for the said pact, was beyond amusing.
As a being created by the Supreme Beings, Demiurge, of course, stood far above simple demons.
To the free guild's assessment, even the archdemons were only special A, and thus much weaker than the upper-tier demons he could create with his |Lord of Evil| skill, not to mention the seven evil lords in his service.
Thus, even if the demons summoned from this reality proved to be too arrogant, he could just dismiss or eradicate them with ease.
'I guess it's time to begin. Albedo has received my daily reports, and there was no mention of the Supreme Beings requiring my services today.'
The Blazing temple, located in the heart of the seventh floor of Nazarick, was his dwelling. From an outsider's point of view, the temple looked decrepit, but to him this was the very expression of his Creator's care for him. Lord Ulbert had built the temple with great care to reflect his son's dark and ruinous nature.
Demiurge stood in the center of the main floor with a pile of kijin bodies beside him. Kijins, as a relatively high-ranked race, were good enough forms for even high-ranking demons to inhabit when summoned, and surely were an adequate tribute.
'Let's see. Three should be a good start. Statistically, at least one of them will be reasonable enough to agree to be a test subject.' Demiurge mused.
Adjusting the summoning ritual for his use was child's play. He casually took the three corpses, one by one, and dropped them in the cleared area. What demons would require to rebuild these bodies to suit their needs would be taken from Demiurge's massive magicule reserves.
Once the three bodies were secured, he cast the summoning spell with a clear requirement to agree to participate in whatever tests he deemed fit to perform in his nightmare realm.
Almost instantly, three corpses morphed into three figures who slowly rose.
Two of them were clad in black clothing from head to toe with completely black eyes and hair. The third one was dressed in a black suit with white and purple accents, fitted for a ruler. Unlike his peers, his hair had a few streaks of red and gold in them, and had golden pupils in his otherwise black eyes.
He stepped forward and bowed while the other two demons kneeled. "Finally, I have been summoned. You have my gratitude, Lord Demiurge."
Demiurge observed the trio carefully. The one who stood out was miles above the other two in terms of power. By raw power alone, he was equal to the evil lords, if not surpassing them. The other two were pretty much fodder in comparison.
"You agreed to be my test subjects. What do you require as payment." Demiurge said, giving them a professional smile.
"You can use those two however you wish, Lord Demiurge. They are of no consequence. I agreed to your summons for one simple reward." The demon replied with the exact same smile as Demiurge. Even his speaking tone was somewhat similar.
"And what purpose might that be?" Demiurge asked. The demon before him exuded confidence. Removing him likely would end with massive structural damage to the seventh floor of Nazarick. Someone on an evil lord level would be enough to pulverize anything but the strongest denizens of Nazarick, which as tests showed would threaten the integrity of the Tomb.
Thus, an instant removal, even in face of such arrogance, was not the most optimal path to take.
"To serve the rulers of Nazarick, of course. You already have granted me a permanent body, so no additional payment is required." The demon said with another bow.
"How intriguing." Demiurge remarked, eyeing the demon curiously. 'He already knows about Nazarick. That means he answered the summon specifically for this purpose. This demon could be a decent asset to Nazarick. If no additional upkeep is needed there is no downside to letting him join the ranks of Nazarick. But such a decision should be made by Lord Momonga, not me. If he agrees to complete servitude, then as a demon he should not be able to break it.'
He quickly took out a pocket watch to see if it was past his master's official working hours, and seeing that about an hour was left, he immediately sent a message. { Lord Momonga, I apologize for bothering you, but I have come into contact with a potential servant who wishes to serve Nazarick. }
{ What sort of servant? And how did he contact you specifically? }
{ I was performing summoning experimentation and one of the demons' is far stronger than my initial research into the topic would suggest possible. To my estimate, he is close to the evil lords in power. }
{ I see. I assume you consider this demon trustworthy enough? }
{ A demon's contract is unbreakable, and he had expressed his wish to serve as a payment. }
{ Very well, bring him to my office. }
"Lord Momonga has granted you an audience. I will say this only once: Show proper respect." Demiurge said as he cast a gate to the ninth floor of Nazarick.
"I would not dream of insulting the great ruler of Nazarick himself." The demon said with a bow.
Just a minute later, both entered Momonga's office. The demon, to his credit, immediately kneeled and exclaimed with a shaky voice. "Lord Momonga, it is an honor to meet you at last! I have come to serve you."
Momonga stared at the demon silently. 'I know what to call him! Why the hell do I know what to call him?'
As he tried to figure out why this kept happening, |Omniscience| gave an unexpected answer. Someone called Rimuru had given the name to this demon in numerous timelines and the imprint was strong enough for Momonga to tap into it through his skill.
'How strange. I guess there is no harm in using the same names. I already used them previously.'
"Rise, and explain why you want to serve Nazarick." Momonga said, staring down at the demon who was kneeling with his head lowered.
The demon stood up and replied with a polite smile. "You, my Lord, caught my attention the moment you arrived in this world. I believe my path forward is to be in your service, and nothing would bring me more pleasure than to be in your employment."
"I asked for an answer, not sweet talk." Momonga remarked. "If my subordinate hadn't vouched for you, I wouldn't have even talked with you!"
The smile on the demon's face faded. "I meant no disrespect. I truly believe that being in your service would be the most beneficial path for me, my Lord. I assure you, my services come with no hidden cost."
"Is that so? Maybe you also know why I already know what to call you? Call me curious, but why would a demon like yourself not only know about us but would also want to be in our service for no apparent reason?" Momonga asked as he stared into the demon's eyes.
'So this demon gets summoned in many timelines, same as the ogres come into service of this Rimuru. Could it be that we arrived as his replacement? Or maybe he would show up one day?'
Momonga once again tried to make |Omniscience| corporate and provide answers, but the only piece of information the skill provided was the fact that the entity known as Rimuru didn't exist in the current timeline because Momonga and Nazarick by extension arrived in its place thus making Rimuru's appearance very unlikely.
The demon returned his gaze with a wary expression. "I was not aware you would know of such a thing, nor did I expect you to give me a name. Truth be told, you, my Lord, caught my attention the moment you arrived in this world. Never before has such an otherworlder been seen. I could feel within my heart that my place was to be among the ranks of your servants. I apologize, but I have no other explanation to give."
'His responses feel genuine even if he is a demon. Come to think of it, he also seems like Demiurge's brother in terms of mannerisms and sincerity. Either way, I don't have enough energy to name him at the moment.' Momonga pondered on what to do. His careful, and somewhat paranoid side, told him to just dismiss this demon right away, but his instincts told him that the demon was telling the truth.
There had to be a way to figure out what this demon was. 'I wonder if I can use |Appraisal| together with |Omniscience|? I guess I could at least try.'
For once the skill didn't give a vague impression but pretty much opened a wiki page for the demon the moment the appraisal spell was cast.
'So he is one of the seven primordial demons, the progenitors of all demons of this reality. That means there are six more like him and nothing more powerful in the demon ranks than them. He is powerful, but even with a name, he still wouldn't exceed Demiurge's power.'
"So you are a primordial demon?" Momonga said out loud as he processed the information the skill had given him.
"Correct, my Lord. I am known as Noir, or the primordial of black color." the demon said with a hint of pride in his voice. 'How wonderful, my new master already knows who I am. That means nothing could be hidden from him. I can't pass up this opportunity to get in his service.'
"Before I accept your servitude, I need to know what you desire?" Momonga raised his hand before the demon could answer and added. "I don't believe you have come to serve just for servitude's sake."
The demon gave Momonga a professional smile, but that was just a facade. Internally, he went into full panic mode. 'He doesn't believe me? What should I say? No, I can't fail. I won't fail. Think! I know! I will say that my goal was to be named so I would get more power and that I don't mind repaying that debt over countless millennia.'
"I wish to be named. This is the only way I can evolve beyond my current status. In return, I will pledge my full servitude to you. For my kind, time means nothing, so being in your service for millennia or however long you deem my service is required to repay the debt is a small price to pay for the honor."
'So the demon wants power. That was rather predictable, to be honest. But if Demiurge said he would not break his word, then I have no reason to not gain another servant, and a powerful one at that. I think I will have to use Nazarick's reserves on this one. Let's see… oh, the current energy amount is at eighty-seven percent.'
"I will agree to your terms and take you in as a servant for…" 'how much time should I demand? A Thousand years? Two thousand? I better make this a hard bargain to see how serious he is.' Momonga tapped his fingers on the table with his right hand and stroked his chin with his left.
Demon nervously shifted around and watched Momonga contemplate the length of servitude he would demand.
"Five thousand years in exchange for naming you." Momonga said a moment later, gauging the demon's response.
'Is he smiling? Wait, was that a too-short period of time? Shit, I might come off as too soft. Eh, it's too late already. The offer is made.' Momonga continued staring at the demon, blessing the fact that his skeletal face could not betray any emotions.
The demon bowed and said with a shaky voice. "I agree to these terms, my lord. In exchange for being named, I will be in your service for five thousand years, and once the contract ends we can renegotiate it." 'What a relief, I will have plenty of time to come up with a valid excuse.'
"Then, I will call you 'Diablo.'" Momonga exclaimed, drawing the energy from Nazarick's reactor to fuel the naming.
Just as the name escaped his non-existing lips, the demon spread his wings and instantly engulfed himself in an egg-like shape. The amount of energy the demon drew was second only to Rubedo's renaming.
A few minutes later, he emerged from the cocoon, now dressed in a butler's outfit and said with a deep bow. "Thank you, Lord Momonga. I am ready to begin my service. What are your orders?"
To a rough estimate, Diablo was above the evil lords in terms of power, only coming short of the floor guardians. But unlike them, he didn't have an ultimate skill. However, he compensated with a whole array of skills.
Unfortunately, most of them were already on |Nazrick's| list but there was one that was unseen before, |Tempter|.
This skill possessed an ability to create a weaker version of the illusionary world Demiurge could conjure with his |God of Nightmares|. It additionally had |Thought Domination| and |Charm|, making him just as dangerous as Demiurge to an opponent who could not resist its effects.
"For now, you can assist Demiurge in whatever way he needs you to."
"Of course. But if it's possible, I would like to offer a candidacy for the position of your personal butler." Diablo said.
"I already have a personal butler, and I believe your skills would be better utilized under the guidance of Demiurge." Momonga shot him down instantly.
"As you command, Lord Momonga." Diablo said with a professional smile, however, the disappointment in his gait was noticeable. Reluctantly, he followed his new superior to perform whatever duties were required of him. 'I will become your personal servant and nothing will stop me!'
Proofreading by I AM THE STRING CUTTER, Abbysalidiot, RottenPizza, Sad_Smiles, Visur Nyxan, and alassandro.
AN: Thank you for reading the story, and if you have caught up to the latest chapter, you can check out my other work or join my discord server (Link is in my profile) where additional chapters are available.