Sasuke Uchiha in Harry Potter

Greengrass Mansion III

Within Astoria's mind, Sasuke found himself running down a corridor, recalling the time he was inside Naruto's mind along with the Kyubi. Upon reaching the center, he saw a vast chamber surrounded by a sealing barrier, within which a black mass was pounding against the barrier, trying to break through.

Sasuke thought, So this is responsible for the blood curse.

He opened a gap to enter and then closed it behind him.

The black mass lunged at him, but Sasuke evaded and performed hand seals before shouting, FIRE STYLE JUTSU: FIREBALL! He sighed in relief upon seeing his attack hit its mark.

???: HAHAHAHAHAH

A laugh echoed as the flames extinguished.

???: Did you really think it would be that easy to kill me? I have lived for hundreds of years, feeding off the life energy of cursed witches.

The mass began to take shape, revealing a humanoid being with wings and horns.

Sasuke thought, A demon, as depicted in Christian religion. One of the first things he did upon arriving in this world was investigate all existing religions.

Demon: Release me, boy, or you will suffer the consequences. I must absorb the life energy of that girl.

Sasuke: Why would I do that?

Demon: Because if you don't...

The demon vanished and reappeared behind him.

Demon: I will kill you.

Sasuke dodged and quickly moved away.

Sasuke: Are you responsible for this curse?

Demon: Yes.

Sasuke: Do you know how many people you've killed?

Demon: Who's counting? They're merely food. The magic I devour is delicious.

Sasuke grew irritated and charged at him, but a shield appeared, blocking his attack.

Bees made of pure magical energy emerged from the demon's body in large numbers and flew toward Sasuke.

Sasuke: CHIDORI SENBON! — Several needles impacted all the insects, destroying them.

The demon quickly closed in to strike, but Sasuke blocked the attack with his right fist. He punched with his left fist, but the demon dodged by flying.

Sasuke vanished and appeared on the ceiling, facing the demon.

They locked eyes and launched their respective attacks. Sasuke drew his katana, enveloping it in Chidori, while three giant magical wasps emerged from the demon's body.

Both propelled themselves forward, ready to strike. The demon advanced while conjuring two swords made of pure magic.

They began exchanging blows, neither showing signs of stopping. The only sound that could be heard was the clashing of swords. The three magical wasps hung back and started firing energy beams, which struck Sasuke, creating a large cloud of smoke. In the blink of an eye, the three wasps were sliced apart, and when the smoke cleared, no one remained.

Sasuke reappeared in front of the demon, and they resumed their exchange of blows, first with fists, then with swords. The demon flew again, watched by Sasuke.

Around Sasuke, several insects appeared, ready to unleash their beams.

Demon: This is your end; you are surrounded.

All the insects fired, and as the beams approached, Sasuke's body began to emanate a purple aura. The Susanoo, in its second form, appeared and blocked the beams.

The Susanoo opened its right hand, unleashing black flames. It attacked the insects, completely incinerating them.

Demon: What the hell is that? — He thought.

Sasuke glared at the demon and said, Amaterasu.

The demon's arm began to burn, and he quickly tore it off.

Demon: What are these black flames? Answer me!

Sasuke: There's no need, as you will be dead soon.

Demon: These black flames are not ordinary. I tried to extinguish them with magic, but it didn't work. If I hadn't ripped off my arm, the flames would have consumed my body.

Sasuke continued to watch the demon, now missing an arm.

Demon: Don't get too cocky, — he said as he regenerated his arm.

The demon watched Sasuke when he suddenly felt a pain in his chest. He looked down and saw Sasuke plunging the katana into his chest.

Demon: How is that possible?

Sasuke: Does it matter? — He said, slicing the demon in two.

The demon fell to the ground, and Sasuke watched him without lowering his guard.

Demon: Damn it, I thought this would be easier. I guess it's time to get serious. Don't think this is all my power. The Greengrass family curse has existed for about 200 years. How much magic do you think I have devoured?

The entire body of the demon strengthened; his muscles grew, and his body expanded.

In the blink of an eye, the demon appeared and pierced through Sasuke's body, which exploded, revealing it to be a shadow clone.

The demon was ready to strike the Susanoo. Sasuke remained serious and said, Amaterasu, but the demon vanished quickly.

The ground began to deform, creating worms that started firing magical energy beams.

Sasuke: At this rate, this battle will end due to exhaustion.

The demon flew around Sasuke but stopped to dodge something.

Demon: What was that? — He thought, realizing that the Susanoo was equipped with a bow and arrow.

The demon flew rapidly while dodging the arrows.

Demon: What is happening? It seems he can anticipate my movements. — He thought.

Sasuke: He's becoming unstable. — He thought, continuing to fire. The demon couldn't react in time, and an arrow struck him, severing an arm and a wing.

Demon: DAMN IT! — He yelled as he regenerated his arm and wing.

Sasuke: It's time to end this. — The arrow from the Susanoo was enveloped in Amaterasu.

Demon: I tricked you. — He said with a smile. He swung his arm, and two ropes emerged below Sasuke, binding his arm. The demon pulled him out of the Susanoo, yanking him closer. The emo took a blow to the stomach, and in pain, he spat saliva, but the demon didn't stop; with both hands, he began to strangle him.

Demon: Did you really think you could defeat me, mortal?

Sasuke: Damn it, I let my guard down. — He thought while trying to put him in a genjutsu, but it wasn't working.

Demon: You're trying to put me in an illusion, aren't you? That doesn't work on me.

Sasuke was feeling breathless and started to lose consciousness, but suddenly the demon was sent flying backward by a kick from someone wearing a black cloak with red clouds.