William let out a primal roar. His hands extended into serrated blades, lashing out at Ron, Sami, and Rad. The brothers leaped away just in time as the blade-arms sliced through nearby buildings like butter.
Ron teleported, his Blade of Vengeance crackling with lightning. A surge of electricity slammed into William, forcing him back. Seizing the opening, Ron blinked behind him, delivering a brutal combination: a punch to the jaw, a knee to the gut, and a final strike that sent William hurtling fifteen kilometers away.
"Let's end this, Sami," Rad said, his eyes locked on Ron.
Sami hesitated. "Careful. I think he's hiding a trump card."
Rad nodded grimly, coughing into his hand. "Then what's the plan?"
"I need you to get that weapon. It's the only way to finish him."
"I'm not leaving you alone!" Rad protested.
"Go!" Sami countered. "I'll stall for time." Before Rad could argue further, Sami rushed toward the fray.
In the center of the crater, Ron hacked through the monster's four arms, but they regenerated instantly. Gritting his teeth, Ron channeled a purple aura into his blade. For a split second, his eyes flashed a predatory red.
For the first time, William saw his own death.
As Ron swung for the killing blow, William triggered his ability. Space distorted, and they swapped places. Now, William held the blade, thrusting it at Ron's chest. Ron reacted instantly, manifesting a purple armor around his palm to catch the blade. The steel pierced his skin, but Ron didn't flinch. He lunged forward, catching William with a shattering uppercut.
"No... I can't lose!" William snarled. He unhinged his jaw, erupting a torrent of flame. Ron teleported above the blast and hammered William into the ground with a falling strike. He summoned his sword again, aiming straight for the throat.
William manifested more blades to parry, forcing Ron back with a series of shallow cuts. William stood up, his body shifting. "You are strong. But not strong enough."
A double layer of plate-armor encased his body. He tripled in size; a heavy tail slammed the ground, and a massive horn sprouted from his skull.
"He's not human anymore," Ron muttered.
William flicked a needle toward Ron. Ron raised a hand to swat it away.
"Ron, no! Don't touch it!" Sami screamed.
It was too late. The needle grazed Ron's palm. William let out a jagged laugh. "You fool."
Ron's vision blurred. His strength evaporated, and he collapsed to his knees.
Flashback
"Keep these with you," Dr. Ignes had said, handing William the silver needles. "Use them only when necessary. They are fatal."
"What are they?" William asked.
"A gift," Ignes replied. "Extracted from the blood of the old Watchers. With my modification it has a became almost like a poison for Black Sorcery Users and even for Watcher himself."
Present
What is happening to me? Ron thought, his body feeling like lead.
Sami rushed in to cover him, hurling spears of white-hot flame. William dodged, sweat breaking out on his brow. His flames are different... I have to be careful. Suddenly, Rad appeared from the flank, wielding twin swords made of pressurized wind. He unleashed a whirlwind of strikes, pushing William back.
I need distance, William realized. He kicked Rad away and extended his blade-arms.
"WIND SHURIKEN!" Rad roared.
A massive, spinning blade of air materialized and tore through William's arms, disintegrating them on an atomic level. Rad fell to his knees, coughing up a spray of blood.
William stared at his vanishing limbs in horror. He destroyed them at the atomic level? He forced his body to regenerate, then began telekinetically hurling chunks of the ruined city at the brothers.
Rad raised a barrier to block the debris, while Sami ignited his own flaming swords and charged. William summoned four blades of his own, meeting the brothers in a chaotic symphony of steel and fire.
Suddenly, Ron reappeared. Blood wept from his eyes, his face a mask of pure rage. With a single, earth-shaking punch, he shattered William's double-layered armor. Ron gathered lightning in one hand and fire in the other, coating both in a terrifying purple aura.
He thrust both palms into William's face. The resulting explosion was the largest the world had ever seen.
When the smoke cleared, William remained standing, though half of his face and body had been turned to ash. He let out a dry, rattling breath.
"I never thought you'd be this strong," William rasped. "You might be the toughest opponents the Fosters have faced in centuries. But now... the game ends."
A suffocating dark aura expanded, swallowing Ron, Rad, Sami, and the entire battlefield.