DISCLAIMER: I do not own Buffy the Vampire Slayer or Devil May Cry.

The dark demon dimension rolled open, and Vergil reappeared in the real world. He manifested an identical copy of his lost sword Yamato, and fired blasts of energy into the town, destroying several city blocks in an instant.

Buffy pulled out her stake. "I'm killing this thing."
A hand gripped her shoulder, and she turned to see Willow.
"Buffy, what about Dante?"
Spike stepped forward, looking sad. "Dante already came to fight this guy. If this guy's still here, it must mean Dante lost."
Buffy felt tears fill her eyes. "Dante…"

They turned when a motorcycle pulled up beside them. The unmistakable form of Trish dismounted.
"That's Vergil, Dante's twin brother. He's the only one who ever really beat Dante, and it looks like he's now got the combined power of Mundus and Argosax, in addition to his own. I can't think of a more dangerous enemy."

Vergil sensed the power of the demon Trish nearby. She was Dante's friend. He turned his attention towards the group that surrounded Trish, thinking of what he could do to them.

Trish stepped forward. "I'll see what I can do. Willow and Tara have to help me."
The thousands of demons that had appeared from the ground suddenly turned their attention towards the group, as if following some silent command from Vergil.
Trish fried the nearest ones with her lightning, instantly killing dozens of them.
"Buffy, Spike and the rest of you, you fight these guys. I gotta focus on the big guy."

Buffy and Spike started fighting the demons. Buffy staked a large demon through the chest, but it survived, striking her across the road. Spike jumped onto the demon's head, breaking its neck. Another demon snatched Spike from the corpse of the first demon, and Buffy flung her stake into its eye, killing it before it could tear into Spike with its claws.

Trish shoved through the crowd of demons, heading for Vergil. Vergil hovered above the ground, waiting patiently for her, like a spider waits for a fly.

Trish reached Vergil, and he casually lowered himself to the ground. Trish fired lightning at him, feeling the witches bolstering her power. Vergil didn't even move, the lightning hitting his chest, not even hurting him. Trish then pulled out her guns, firing shots into Vergil's chest, but the bullets were vapourised before they even reached him, despite Trish charging them with lightning. Vergil calmly moved closer to Trish, his face a completely blank mask. Trish slammed her foot into his groin, putting all her strength behind the kick. The kick had more than enough force behind it to shatter a brick wall, but Vergil showed no sign that he even felt it.

Trish rolled her eyes, feeling powerless. "Did that even hurt?"
Without responding, Vergil sprang into action. With a single thought from Vergil, the world, and the entire universe, froze. He created a large sword from nothing, preparing to sweep it through Trish's chest, slicing her in half. Before he could, he was gripped and forced back by someone who had just appeared.

Vergil released the passage of time, and the world resumed spinning. Trish fell back, stunned, and someone else stepped up to take her place. The man had white hair similar to Dante and Vergil's, but he was younger. He wore a blue coat made of heavy material, with a red hooded jacket underneath. His most notable feature however, was his right arm, which was composed of a crystal substance which glowed blue with an unworldly light. Vergil smirked. "You must be Nero."

Nero smirked back. "So my reputation precedes me."
Nero swung his sword at Vergil, hitting Vergil square in the forehead, but it did not so much as cut his skin, or hurt him at all. Vergil gripped the blade of the sword. "This is mine."
Vergil took Yamato back from Nero, throwing the other devil back. Nero drew his original sword, the Red Queen, and charged. Nero began striking Vergil repeatedly, but the blade of the Red Queen simply couldn't break through Vergil's power. Holstering his sword, Nero started striking Vergil with his crystallised right arm, the arm growing to the size of a double decker bus. Despite this, he was still unable to hurt Vergil at all, his giant, almost indestructible fist hitting a completely unyielding, unbreakable object that took the form of Vergil's face.

Finally, Vergil grew bored. With a flash of movement, he swept Yamato through Nero's chest, cutting him in half. The wound sealed up instantly, which kept Nero in one piece, but the immense demonic power that lived in the blade had been struck straight through his core, and he found himself at death's doorstep, horribly effected not by the blade itself, but by the magic that composed it. Vergil stood over Nero. "I am ashamed to call you my son."
Nero glared at Vergil, horrified. "Your son?"
Vergil forcibly pulled Nero to his feet, glaring into his eyes. "You are my son. It is a title you do not deserve."
Nero spat blood at Vergil's face, but Vergil's energy aura vapourised it before it even reached him.
Vergil effortlessly lifted Nero off the ground by the neck, preparing to destroy his own son.

Willow and Tara had both been injured when Vergil had overwhelmed Trish's magic. Tara had fallen to the ground, her nose bleeding, but Willow was still standing, albeit only barely.
Willow focused on Vergil, who held Nero up by the throat. Using every ounce of the considerable power she possessed, Willow attempted to perform a quick spell on Vergil that would rob him of his powers. The spell was invisible, but she felt it fizzle out, not coming close to breaking through Vergil's energy aura. Now utterly spent, Willow collapsed on the concrete, her nose bleeding badly.

Buffy and Spike were now the only ones left standing on the street, fighting the demons.
Xander had been wounded by a demon with long claws, and Anya had half-carried him away. Giles and Jenny had left to get Dawn and Joyce out of the town. Oz and Larry had collected Willow and Tara, Larry carrying the unconscious Willow with Oz supporting the semiconscious Tara. Buffy gripped Spike by the shoulder and pointed at Vergil, who was torturing Nero by burning his skin with an energy field composed of dark magic. Spike nodded, picking up a sharp blade that had come from one of the demons. Spike charged at Vergil, but the blade was completely erased from existence when Spike swung it, vapourised before it even reached the self-appointed Demon King. Spike was then sent reeling back by an unseen force. Buffy and Spike looked on in horror, amazed at Vergil's power.
Buffy lowered her head. "He's too strong. Nothing can even hurt him."

As Vergil was about to finish Nero off, Trish jumped at him, firing a huge amount of lightning at him. Vergil actually felt it this time, and recoiled, dropping Nero. Nero started to stand, but an explosion of devilish power blew him straight down the street. Buffy and Spike were hit with the shockwave from the explosion, and were blown to the ground. Buffy thrashed, her head ringing, her ears bleeding. Spike had fared better from the explosion, but had landed on his head when he had been blown down, and was unconscious. Buffy struggled to her feet, but her remaining strength rapidly failed her, and she hit the ground again.

Nero had been knocked unconscious by the blast, but Trish had managed to withstand it, using a very powerful blast of lightning as a shield. An utterly exhausted Trish staggered, amazed at the strength it had taken to even survive the repulse of devilish dark energy. As she began to raise her hand to throw more lightning, Vergil focused on her, and her insides boiled. She hit the destroyed ground, struggling to breath. A normal human would have exploded, but Trish would stay alive with her insides boiling for several minutes. She tried to stand, but Vergil altered gravity, causing her knees to give out. Vergil glared at his defeated foes, all of which had been no challenge at all.
"No one can stop me! I am God!"

In the dark demon dimension, Dante teetered on the brink of death. His body was destroyed, but his soul lingered in the dark world. He could feel power and destruction outside. He tried to remember what was happening, but he couldn't. He was too tired.
The darkness began to overcome his consciousness, and he was slipping. Just as his disembodied soul was almost completely faded away, he remembered. "Vergil!"
As the void struggled to take hold, Dante resisted.
"No! I won't fade! I have to stop him! I have to save them! You're not stopping me!"

There was an explosion of red energy as Dante blew the void apart, reappearing in a fully embodied state, though in his devil form. That same explosion split open the demon dimension he was in, destroying it, and he found himself standing back in Sunnydale, directly in front of a surprised looking Vergil.
"Hey there, big bro. How could you throw this big party and not invite me?"

Vergil snarled with rage, and morphed into his gigantic fallen angel form, charging at Dante. To his utter disbelief, Dante blocked his attack head-on, stopping him in his tracks with little effort. Vergil released a repulse of devil power, but Dante morphed into the imposing Majin form, and the repulse was stopped dead in the air, freezing and literally shattering as if it were made of glass. Vergil attempted to release more earth shattering attacks, but Dante's Majin form proved powerful enough to stop Vergil's deadliest attacks before they even started, his magic attacks turning to glass and shattering before they could do anything, and his physical attacks stopped with little effort. Horrified, Vergil released the full extent of his newfound power, launching himself at Dante with reality warping around him, as if making way for a king. Dante released his own dimension altering power, and the two arch devils clashed in a massive display of limitless power, a pocket dimension surrounding them and containing their cataclysmic battle.

The power compressed to the point that it exploded, and the entire planet shook on its rotation axis despite the explosion happening in a parallel dimension. When the dust of the destroyed street and the obliterated pocket dimension cleared, Dante, back in his human form, stood over the humanoid form of Vergil, who now seemed completely weak and helpless.
"Taking the power of Darkness Mundus and Argosax the Chaos may sound big, but I'm the guy that killed both of those douchebags. You see Vergil, you can be as powerful as you want. It doesn't change who you really are. For all that power, you're no stronger now than you were all those years ago when I beat you at the waterfall. If anything you're weaker. You surrendered the last of your humanity that day, and someone who has no soul, no ability to feel love, can never defeat a person with a real soul. That's why demons are actually weak. Welcome to the world."

Buffy stood, heading over to Dante. Dante glanced at her sadly, before pointing his gun at Vergil and pulling the trigger, firing a shot imbued with tremendous devil power, erasing Vergil from existence, leaving only his sword Yamato behind, buried in the rubble from the shredded road.

Dante felt tears fill his eyes, and Buffy hugged him comfortingly. Spike stepped over to the group, helping Trish and Nero to their feet. Trish rested her hand comfortingly on Dante's shoulder, while Spike supported Nero, who still couldn't stand.
Clearing his eyes, Dante turned to regard the wounded Nero.
"At least you got your sword back, eh, kid?"