He Rapid Slashed at Enzeru, who blocked the attack by drawing out his sword and guarding with it.
But Vergil had been expecting this and turned around, slashing at Enzeru's back.
Once again he blocked, however, Vergil used his greatly-increased strength to throw the sword from Enzeru's grip and into a building.
After that he kicked Enzeru across the street, right behind him the whole time.
When he landed Vergil was already there and stabbed through his stomach, then twisted, pulled the sword out and slashed across his chest as he finished the spin.
Enzeru stumbled back then looked up and his eyes were bluish white, as were the flames surrounding his hands.
He smirked and threw the fire at Vergil, but he air-tricked past both the fireballs and Enzeru, performing a Rapid Slash as he did so.
Again Enzeru was forced to stumble but this time moved right into Vergil, who was waiting in the special Judgement Cut stance.
Enzeru barely had the chance to look up before he was entrapped in a sphere of black hell.
When it disappeared the forearms of Enzeru's overcoat were gone and his wounded arms came away from his face, which was covered in cuts.
Vergil smirked, though his demonic mouth was much bigger so it only just barely parted.
"You will not forget this devil's power." He said before air-tricking out of sight and filling the area with more spheres.
He watched in what he noticed was some kind of joy as Enzeru ran to his sword and tried to dodge and block off the strengthened attacks.
Enzeru was failing at it.
By the time Vergil had finally finished and came back down, dramatically sheathing Yamato, Enzeru's overcoat had various cuts and tears in it and his body was washed with the crimson redness of his own blood.
Yet he was still grinning.
Vergil didn't particularly care though, not anymore.
All he cared about was killing him and taking both the title and power of demon-king for himself.
"Where's your motivation?" He taunted the wounded man.
Enzeru looked up at him again and his grin turned into a smirk.
"You certainly are stronger than this little human form of mine can handle. I admit, if I'd still been fully human this would be the end."
Vergil's eyebrows would have furrowed if he had any right now.
He'd assumed Enzeru was always a demon, just with a human shape.
Still, it didn't matter.
He rushed towards Enzeru and sliced at his neck, ready to end this.
Surprisingly though, a strange-looking hand grabbed the blade and held it still.
Then Enzeru looked up at him again and Vergil could see his teeth; now bleached white with sharp pointed ends.
His eyes were pure, radiating yellow now, though that bluish white fire seemed to sieve out through the sides of them.
"Considering you're a half-demon yourself, you of all people should know that all half-demons have a human form and a demon form."
Enzeru pushed Vergil back and swiped at him just to make sure he would back away to a safe distance.
"When I became the dark knight after being trapped in this demon world I was transformed partially into a demon, though because of my already strong powers I retained some human within myself as well."
His overcoat turned into a cape, filled with the purple color back in his room and trimmed on the sides with white.
His crimson-colored gloves fused into his hands and made the now gauntlet-like fists the same color.
His arms and legs were now covered in white "armor" which looked like a much harder and segmented version of Vergil's skin, despite the change in color.
The armor-plated vest that he wore before was now replaced with an elaborate-looking white breast-plate.
His head meanwhile was covered in a medieval-like helm that allowed his long, unchanged black hair to come out the back of it.
"Because of this, my human powers are what I usually use, as no opponent in the past has been worthy of my showing this form to them. This is my devil form."
Vergil stood there, frozen.
In the blink of an eye Vergil was penetrated by countless ghost swords; once simply bladed shapes, now all resembling Enzeru's sword down to the finest detail.
They erupted and engulfed Vergil in the blue-white flames that burned through his demonic flesh until they and his devil form were gone, him kneeling on the ground in his human state.
He looked up at Enzeru and didn't see an amused look as he'd expected to.
"Vergil, your devil-power is indeed superior to my human abilities. And considering how premature your strength is, it would have been stronger than my demonic abilities as well."
His gaze fell back to the ground, unable to look up anymore because of the strain it put on his body.
"But I have had centuries to hone and perfect my power, unhindered by any morals or ambitions other than getting stronger. You have had decades, and now have something you wish to do more than simply gain power."
Vergil fell down, only holding himself up with his arms.
"I meant what I said before; you are too inexperienced, even as much as you have learned in this short period of time, to defeat me."
Then he fell down all the way, watching the blood pool out in front of him.
Enzeru's form had returned to its human shape and Vergil heard him sheathe his sword.
His vision started to fade and he felt the last remaining strength in him leave.
"Be grateful… that you do not have what it takes to defeat me."
Vergil's eyes closed and his body went limp.
"It isn't worth it."
Even shorter than before but it got the point across. I'll update again before noon but I'm not sure when exactly.