The Blood God In Chaldea

Void

They both charge at each other, their swords colliding with a ring of steel echoing through the battlefield. The red knight parries a blow and then strikes the demon's shoulder, drawing blood. 

The Alastor screeches, Mordred raises her sword, ready for the final blow, but the demon disappears in a flash of bright light.

"What The-" Mordred gasped as she immediately searched around her

Suddenly, Alastor appears behind Mordred, his eyes glowing red. Mordred dodges a swipe of the his sword and ducks under another attack.

Mordred jabs his sword at the demon's chest, drawing more blood. The Alastor howls in pain and stumbles back, giving Mordred an opening for one last attack..

But it was planned from the very start

"Counter!" He Activates before the sword reached his chest

Mordred knew something was wrong and tried disengaging but there was Newton's second law that prevented her from stopping so the best she could do was reduce the damage.

Mordred's sword clashed against a dark energy that rose up to block her attack. The energy was so powerful that it threw her back, causing her to stumble and lose her balance.

Alastor took advantage of the situation and launched himself at her with blinding speed. His sword flashed with an unearthly light, cutting through the air towards Mordred's heart.

Mordred tried to block the strike with her own weapon, but it was too late. The demon's sword cut through her armor and into her chest, causing her to screech in pain.

Despite her injury, Mordred somehow managed to stay on her feet. She summoned all her remaining strength and charged towards the demon, desperate to end the fight before it was too late.

Alastor sensed her approach and swung his sword, but Mordred leapt over it, delivering a powerful blow to his head. The demon's body crumpled to the ground, his sword falling out of his hand.

Mordred collapsed next to him, gasping for breath and struggling to stand. She had won the battle, but at what cost?

But that felt too easy. Mordred knew it wasn't over, and she was right

Mordred turned her head to the right and saw him. Watching her while eating the flesh of a dead human that had orange hair.

"You fucked everything up." Alastor's voice was trembling. 

"MY REVENGE IS GONE!" He threw the head he had like a drunken deadbeat father

With a terrifying roar, Alastor charged at Mordred, his claws glowing with crimson light. She tried to dodge, but he was too fast. He slashed her across the chest, leaving her struggling to stand.

Alastor grinned widely, revealing the sharp fangs in his mouth. "Die, you useless knight! You've ruined everything!"

Mordred's vision blurred, and she fell to her knees. The world started spinning, and she knew she was dying. As she slipped into unconsciousness, she saw Alastor standing over her, his eyes glimmering with pure evil.

"No... Death is too nice for you.. My body is useless now because the master had died.. So, Give me yours" Alastor's mind breaks