In contrast, the undead Momonga's divine class items did not have any data which protected against mind-affecting effects. But in that case, why did Momonga not feel fear?
There were two possibilities.
He might have resisted it with his base stats, or resisted it with his immunities from being an undead creature.
Because he was not sure which hypothesis was correct, Momonga decided to conduct an experiment:
"Can you try using other effects?"
Aura tilted her head and made a strange noise of bafflement. Momonga was reminded of a puppy, and he reached out to stroke Aura's head.
Her hair and scalp felt smooth as silk, and caressing her was very comfortable. Because Aura did not seem to mind, Momonga wanted to keep going on. However, Mare looked a little frightened as he stared at them from the side, so he paused.
What was Mare thinking, anyway?
After thinking for a short while, Momonga released his staff and ruffled Mare's hair with his other hand.
The quality of Mare's hair felt better, but Momonga hardly paid it any heed as he rubbed their heads until he was satisfied. Then, he remembered what he was here to do:
"Then I have something to ask of you. I plan to conduct certain experiments… I'll need your help for them."
At first, the two of them did not know how to respond to that. However, when Momonga's hand left their heads, the two of them had embarrassed yet happy looks on their faces.
Aura cheerfully replied, "Yes, I understand! Momonga-sama, leave it to me!"
Momonga reached out a hand to quell Aura.
"Before that—"
Momonga gripped the floating staff in his hand.
Just like before, when he used the power of the ring, he focused on the staff. Among the many powers it possessed, Momonga concentrated on one of the gems which decorated the staff.
It was a divine class item called the Gem of the Moon, and the ability Momonga chose—
—called forth Moonlight Wolves.
As the summoning magic took effect, three beasts appeared out of thin air.
The special effects of the summoning were the same as in YGGDRASIL, so Momonga was not surprised by them.
Moonlight Wolves looked very similar to Siberian Wolves, but they radiated a silver glow. Momonga could feel a mysterious connection between himself and the Moonlight Wolves. It clearly showed who was the master and the servant between them.
"Are those Moonlight Wolves?"
Aura's tone showed she did not understand. After all, she had no idea why Momonga would summon such weak monsters.
Moonlight Wolves were highly agile and they were useful for ambushes, but they were only level twenty or so. They were very weak monsters compared to Aura and Momonga. However, monsters of this level were enough for their purposes this time round.
In fact, the weaker they were, the better.
"Yes, they are. Now, include me in the radius of your skill."
"Eh? Really?"
"It's fine."
Momonga's insistence was so great that even the dubious Aura went ahead with it.
Given that they were no longer in the game, there was a possibility he could not ignore, which was that Aura's skill might not have activated properly. In order to rule that out, he had to expose himself to the skill with a third party, which was why he had summoned the Moonlight Wolves.
After that, Aura exhaled several times, but Momonga did not feel affected in any way. He tried relaxing or turning around in the middle of the skill, but he felt nothing strange. However, the Moonlight Wolf behind him was affected. Thus, he concluded that Aura's skill had taken effect.
From this experiment, Momonga learned that mind-affecting effects did not work on him. This meant—
In the game, demihuman and heteromorphic races unlocked racial skills when they reached certain levels. An Overlord like Momonga had the following skills:
Create High Tier Undead four times per day, Create Mid Tier Undead twelve times per day, Create Low Tier Undead twenty times per day, Negative Energy Touch, Despair Aura V (instant death), Negative Protection, Dark Soul, Black Halo, Undead Blessing, Unholy Protection, Wisdom of Darkness, Speak Evil Tongues, Ability Damage IV, Piercing Damage Resistance V, Slashing Damage Resistance V, Turn Resistance III, High Tier Physical Immunity III, High Tier Magic Immunity III, Cold, Acid, and Electrical Immunity, as well as Arcane Vision/See Invisibility.
And then there were the abilities from his class levels — Instant Death Magic Enhancement, Rite of Darkness, Undead Aura, Undead Creation, Undead Control, Undead Strengthening, and so on.
Then there were the basic special qualities which all undead possessed:
Immunity to critical hits, mind-affecting, poison, disease, sleep, paralysis, death, and energy drain effects. Resistance to necromancy and biological penalties. Undead did not need to breathe, eat, or drink. They were healed by negative energy and had darkvision.
Of course, they had weaknesses too, like Good, Light, and Holy Vulnerability IV, Bludgeoning Vulnerability V, Vulnerability to Holy and Good Consecrated Areas II, double damage from fire, and so on.
—This meant that Momonga could be sure that he still possessed the basic abilities of an undead being and his special skills gained through levelling up.
"I see. Well, this was an informative experiment… thank you, Aura. Are you all right?"
"Yes, I'm fine."
"Is that so… return."
The three Moonlight Wolves vanished as though time itself had turned backward for them.
"...Momonga-sama, did you come to our floor in order to perform those experiments just now?"
Mare was nodding beside her.
"Eh? Ah, no. In truth, I came here for training."
"Training? Eh? For you, Momonga-sama?"
Aura and Mare's eyes were so wide it seemed like they might fall out of their sockets. Their surprise was only natural; after all, who would expect to hear such a thing from Momonga, a powerful magic caster, the Supreme Ruler of the Great Underground Tomb of Nazarick, as well as the one who stood above all?
Momonga, who had anticipated this reaction, swiftly replied:
"Indeed."
After seeing Momonga's swift reply and hearing the light impact of his staff on the ground, realization dawned on Aura's face. Momonga was quite pleased with himself, as this reaction had fallen within his scope of prediction.
"Is, is that the legendary weapon of the highest order which only you may wield, Momonga-sama?"
Legendary weapon? What did he mean by that?
Momonga had his doubts, but after seeing Mare's shining eyes, he knew the question had not been asked with ill intentions.
"Indeed, this is the Staff of Ainz Ooal Gown, which I made with my guild members."
Momonga raised the Staff, and it immediately radiated a beautiful glow which lit up its surroundings. The glow was as blinding as the Staff itself. However, the surroundings were filled with inauspicious flickering shadows, which emitted an aura of menace.
Momonga's voice was more animated and proud when he spoke:
"The seven gems in the Staff's snake mouths are all divine class artifacts. Since they all belong to a set, having them together unlocks even greater power beyond their base abilities. Gathering them all required an incalculable amount of time and effort, and many of our members stated that they wanted to quit during the process. I can't remember how many monsters we farmed for their drops… anyway, in addition, the Staff's power is beyond that of a divine class item. In fact, it almost approaches that of a World Class Item. Its most potent feature is its automatic engagement system… cough, cough."
...It would seem he had gotten carried away.
He had built it with his comrades in the past, but because he had never taken it out before, there had been no chance for it to shine. Now that he had the chance to show it off, his praise surged forth like a rising tide. Momonga forcibly quelled his desire to flaunt the Staff.
How embarrassing...
"Mm, something like that."
"That, that's amazing…"
"That's totally awesome, Momonga-sama!"
Momonga almost laughed as he saw their eyes. He tried his best to suppress the delighted expression on his face — although skeletons had no expressions — and continued:
"Which was why I wanted to run some experiments with this Staff. I hope you can help me."
"Yes! Understood! We'll go prepare right away! Then… could we see the power of the Staff?"
"Mm, that's fine. Then, I shall show you a fraction of the power of this mighty Staff, which only I can wield."
"Awesome~" Aura exclaimed as she jumped up and down adorably.
Mare was hard-pressed to hide his delight, as could be seen from the twitching tips of his ears.
Ah, this is bad, I can't let my stern facade slip because of this. Momonga tried to regain his dignity as he reminded himself thusly.
"...And there is one more thing, Aura. I have already ordered the other Guardians here. They will arrive within the hour."
"Eh? Then, then we need to get ready for—"
"No, there is no need. All you need to do is stay here and wait for them."
"Is that so? Hm… all the Guardians — that means Shalltear's coming too?"
"All the Guardians."
"...Haa."
Aura's long ears suddenly drooped.
However, Mare's reaction was not as exaggerated as Aura's. According to her backstory, Aura was designed to have a poor relationship with Shalltear, but that was probably not the case for Mare.
What would happen next? Momonga sighed quietly.