The contestants today may seem similar on a surface level. Each one is a powerful sorcerer who rules over an unconquerable dungeon of their own creation, adored by subjects they ruled over, and trained safely in a mundane world. The parallels end here, however.
Diablo is a nervous humanitarian, wanting nothing more than to protect those he holds dear, yet is stuck being too anxious to be honest with anyone.
Ainz is a man who misses his friends, someone who would sooner sacrifice all of humanity to ensure his and his followers' safety than use his power to stop a war.
The two have time to prepare the weapons they would use in battle, knowing that anything they use will be restored, but not anything about the other opponent. We will start this battle just before the confrontation, right after they've chosen their equipment, from Diablo's perspective.
A large iron door stood fast in front of an ominous man with dark horns contrasted against his pale hair. His stiff and stoic stature might make him seem confident, but he wasn't. 'How did I even get into this situation?' he wondered to himself.
He was panicking. 'I don't know anything about whatever I'm going against. I need more prep time, dammit! If this were a game, I'd leave some awful reviews! I'm going to have some words with the arbitrators later. . . Though, I have to admit, I am kind of excited for the fight.'
His anxious thoughts didn't make it to the surface, however, as the door slowly creaked open, the light of the arena flooding the dark tunnel. Resisting a flinch, he confidently left his area and strode into the arena.
Ainz situation was much the same.
The large figure stood before the dark iron door. Despite his stillness, his mind was racing. 'What kind of opponent is going to be out there? I can't believe they didn't tell me more!' He was upset about the lack of information given to him. 'Well, that's a lie, I can totally believe it. But I'm still mad about it!'
Despite his worries, he still had confidence in his victory. The huge doors opened heavily, letting a bright light flood the room. 'Well, I guess it's time.' He left the room with as much majesty as he could muster.
The crowd went silent in anticipation as the large Iron doors opened. It was a still moment before there was any movement. The audience was composed of mostly gods, both born and made, but any omnipotence they might have had didn't work here. The only mortals allowed were those close to the ones fighting, so it was a different kind of excitement that held them quiet.
With the competitors both being self-proclaimed demon lords, there was a particular interest to see which one really lived up to the title, and a few specific guests who felt close to the match, despite not knowing either.
A deafening roar was let out as both entered the arena at the same time. Both exuded a haughtiness that implied they held a supreme confidence. The similarities would have been more noticeable if not for the extreme difference in physical appearance.
"And who might you be, you silver-haired brat?" Ainz spoke first. 'He looks like a magician, based on that aura. Though, that confident stance makes me not so sure... I'll go into this slow.'
"Keh heh heh, gyah hah hah, AH HA HA! You are a fool not to know of me." There was no way they would know each other. They weren't allowed to, after all. This did not mean Diablo would talk any differently, though. "I am the Demon Lord of another world, Diablo! And who might you be, you oversized skeleton?" Diablo made sure to insult the man back. 'I can hardly see his aura, but that high tier equipment tells me enough. He's a sorcerer of some kind, and a strong one. I'll start with a light push.'
"Ha ha ha, you seem to not know the rules of this place. How would I know of you?" Ainz thought to himself 'It seems almost comical how over the top he's acting.' "But I digress. I am Lord Ainz Ooal Gown of Nazarik. Don't disappoint me, fool. I am quite looking forward to crushing you."
"Oh? You seem confident. Somehow, I can't feel threatened by something that's already died. I'll just kill you again." Diablo readied the Tonnerre Empereur, a staff that could cast one spell up to seven times at once. 'I'm so glad I was given this back. I missed you, staff, even if you're not what I main!' He was crying out of joy on the inside.
Ainz froze for just a moment. 'I suppose it would seem like that. I didn't die to end up like this, though...' His hesitation was not noticed, luckily for him.
"Explosion!" Diablo shouted just before an explosion hit Ainz. His equipment was too high level for him to feel anything, but the smoke blocked his vision for just a moment. He rushed forward out of the smoke to return an attack, but Diablo was out of sight. He cast the spell fly, ascending quickly. 'Shit, I can't believe I lost him so fast.' He cast several self enhancement spells.
'There he is.' Ainz turned around to see Diablo behind him.
A sword of light erupted from the center of Diablo's staff. "Lightning Meteor!"
Simultaneously, seven lightning bolts hit Ainz. He felt no shock, as he was immune to electricity damage, but he still felt a searing radiance. He wasn't hurt all that much, and he wasn't stunned, but the feeling shocked him.
"Undeath army!" Ainz shouted in a raspy, malicious voice. Dozens of skeleton immediately shot up out the ground below Ainz, all focused on their opponent.
Diablo looked shocked. He jumped off the ground and took flight. It hardly took a second for him to drink an enhancement potion and an mp potion before he yelled "Chain lighting!" sending seven lightning bolts from his staff into the crowd of skeletons. They all quickly turned to ash.
Ainz smirked as well as a skull could. "You're too open," he chuckles to himself before calling out "Explosion!"
This spell was much stronger than Diablo's of the same name, but it was a spell all the same.
Diablo smiled, saying "Gotcha," to Ainz.
Ainz heard this an immediately panicked. 'How does he have me, what is he doing!' But it was too late for him to react.
The spell totally rebounded, entirely hitting Ainz. He wasn't immune to spells this high of a level. His concentration now completely broken, he fell from the sky.
Before he could land, Diablo called out "Cross Blizard," forming two massive tornadoes of ice and frost. These threw Ainz Further from Diablo, giving him enough time to recuperate. 'He's smart. Impressive, baiting me into trying to bait him. He's far more clever than most I've fought, and his tactics seem... familiar, somehow.'
Both men were high level gamers extremely invested in PVP, so it was no wonder they could both pick up on that fact in each other.
'I'm glad I'm immune to ice though. That would have hurt me if at least a little if I wasn't.' As he caught his breath, he had time to prepare his hail Mary. Diablo couldn't see Ainz was not caught in the spell, so he quickly took a high-level MP potion.
Ainz had prepared his spell. The 10th level Time stop. He hoped whatever ability Diablo had used before wouldn't work on this too, but it was a risk he was willing to take.
The world went totally still and totally silent. He hesitantly went around the ironically frozen whirlwind of ice. He felt lucky that the spell had worked to freeze Diablo. Knowing he could, he calmly approached Diablo readying his finisher.
"The goal of all life is death. Grasp Heart." He could see Diablo's heart, though it seemed oddly shielded by a purple miasma. Ainz was somewhat worried about this, he didn't like unknowns, but he was overall confident in his ability to kill. As soon as he grasped the heart, though, something strange happened. Diablo's heart was perfectly intact, but the miasma shredded itself before melding into the rest of Diablo. Ainz leapt backwards as fast as he could, sensing the immeasurable energy and violence suddenly spilling out of diablo.
Diablo, course, didn't notice anything in the frozen time. Until he entered it too. He heard Klem in his mind, loud and clear, saying 'He got this demon lord.'
"Klem? Why were you allowed in here with me?!" Diablo shouted out loud to the voice in his head.
'I'm considered one of your power ups, Diablo. But this one isn't like others, Diablo. His magic is stronger than yours, I have no doubt. I'm giving you my powers. Show him how strong the demon lord Diablo really is!'
"Klem, no! I can't lose you again! You really are dying now, I can tell." He was furious that she would do this to him, especially now that he really knew how magic worked.
'So make it worth my while.'
Klem went silent. Diablo knew she was gone. He was left with her power, but she was gone.
The shimmering armor quickly enveloped Diablo. He knew the feeling, and he knew how to use this power.
He shouted in rage, entering frenzy mode.
Ainz decided to end the time stop spell. He heard everything Diablo said, though he had no clue who he was talking to. The sudden transformation caught him completely off guard. He Did not, at all, seem like the same person. Magic now endlessly and violently raged out of Diablo, and his new armor was clearly on the divine level, or at least near it.
The earth-shattering roar that came from it was louder than anything a man could make, and it ushered in an even more violent torrent. but it was nothing compared to what happened when it stood up straight and collected itself. This thing was far stronger than anything Ainz had ever faced up to this point.
Ainz had not been doing nothing during his enemies power up. He Felt the true danger Diablo now posed, and so he casted a 10th level defense spell called Body of Effulgent Bery. He was panicked by the ineffectiveness of his all-powerful instant kill and the sudden, very sharp increase in how dangerous the enemy now was. As he was weaving his next spell, Diablo struck.
It was a direct blow straight to Ainz's core, and it sent him flying into the area wall. If he had not cast that spell on himself, he would have died. That's just how powerful it was. He got to his feet and summoned the best summons he could at the moment, a doom lord. A feeling of sudden impending doom told him to move, even while his emotion suppression kicked in, so he used a teleport spell to go to the other side of the arena.
Just as Ainz suddenly appeared on the other side, Diablo muttered "World Halation." Instantly, an explosion erupted where the doom lord was, so powerful that it felt like the world was tearing itself apart. The only thing Ainz could think to compare it to was a nuke going off point blank. The only reason he was left untouched was because Diablo himself was now in between him and the spell.
Ainz was frozen. His emotion suppression was the only thing saving him at this point. He didn't want to use magic on diablo, he was sure it wouldn't work, but he didn't know what to do. He cast Armageddon, not because he thought it would hurt Diablo, but because he needed time to think.
Diablo calmly left the ground as Ainz was summoning these demons. He accelerated far faster than any of them could, so he wasn't scared. He calmly equipped the two other Demon lord rings he had brought with him. 'Didn't think it would go this far. Oh well.' He felt an incredible surge of power from the ring of madness, even as the ring of ruination striped his ability to use the rest of his spells.
Now ready, he looked towards Ainz. He used sword smite III to instantly close the distance, even though they were so far apart. Ainz was blatantly startled, and he couldn't react.
"Can't teleport away now." Diablo told him menacingly. All the demons rushed back to where the two were, but they were not fast enough. Diablo grabbed Ainz and dragged him upwards at Mach speeds, seemingly leaving the colosseum. Ainz tried to cast grasp heart again, but without the Goal of All life is death to boost it, it reflected back. Ainz was stunned by the spell and could only watch as Diablo said three words.
"Flames of Ruination."
The world went pure white. The pain was indescribable. Ainz could feel his very soul being burned from the sheer, immeasurable, overwhelming heat. He had lost. He could not believe he had lost.
Strangely, he was excited by the idea.
'Finally, a good fight I'm allowed to enjoy.'
Those were the last thoughts Ainz had before being completely evaporated.
Diablo had done it. Ainz was gone, the demons were gone. Klem was gone. He was lethargic from being low on MP, but he felt crushed by his loss.
He descended slowly, the crowd in the stands getting louder and louder the closer he got. As soon as he landed, a voice amplified above the rest announced "We have a winner! True Demon Lord Diablo has vanquished the Overlord! Now take your rest, combatant.
Diablo felt like he never wanted to fight again. He left the arena the same door he entered, though now he felt none of the same joy.