While the fight between father and daughter was happening, Onari hadn't been idle in the background. He continued drawing flaming characters in the air, building up to a formation that could potentially exceed Da Shuizhi's cultivation advantage.
With a final clap of his hands, the spell was cast. A wave of sparks rolled over the room, pushing Da Shuizhi away from Yu Wu. Fire sprung from Onari's core. His whole body was lit alight with raging flames.
A scorching pressure settled over the room. All of the ritual markings smoldered and smoked under the influence of Onari's formation. The air took on a hazy, mirage-like quality and the room's temperature increased even more.
Da Shuizhi stopped his hotheaded pursuit of Yu Wu. He forced himself to regain his earlier calm and turned to look at Onari. A thick cloud of smoke poured out of Onari's mouth as he exhaled. The smoke circled his body, eventually coming to rest behind him in the form of fox tails.
Onari's voice came out as a threatening growl when he spoke, "Your actions have courted death, old man. Your attitude has only sealed your fate. You are a scourge on this world, and I have taken it upon myself to impose judgment in place of the heavens."
Da Shuizhi scoffed, "Better men than you have tried. If I was really so despicable, the heavens would have struck me down years ago."
"Then I guess it's a good thing I'm a fox."
Onari punctuated his sentence with a sudden burst of speed. Clad in fiery armor, he raced toward the demonic cultivator with his new smokey tails held high. Taking a clue from her connection with Onari, Yu Wu darted in from Da Shuizhi's other side.
Da Shuizhi raised his hands to meet Onari's charge. He barely caught a swipe of blazing claws on his forearm, swiftly sliding under the strike so he wasn't burned. One of Da Shuizhi's hands warped into claws of his own and stabbed out at Onari's heart.
Onari's torso twisted, turning the potentially fatal blow into a hit that glanced off the solid flames that armored him. His tails snatched Da Shuizhi's hand as he tried to pull it back. He was stuck for only a single moment, but a single moment was all Yu Wu needed to enter the fight.
Her sword's flames roared as it sliced through the air toward the unwounded half of Da Shuizhi's face. Da Shuizhi grimaced as he was forced to duck towards Onari to avoid the swipe.
A vulpine grin spread over Onari's face. His burning rage was channeled from his core into his hand in an instant. An ear-shattering boom echoed through the chamber as Onari's off hand made contact with Da Shuizhi's chest. Yu Wu's eyes squeezed shut to shield her from the bright light of the explosion.
When she opened her eyes, she saw a scene that would be forever imprinted in her mind. Her father was pancaked against one of the room's walls. He was spread eagle, and hung a couple of feet up the wall like he was stuck there.
Da Shuizhi was dazed for a couple seconds before he managed to shake clear his head and regain his wits. He forcefully pulled himself off the wall, and dropped to his feet. A charred handprint had burned through his clothes and been seared into his sternum from Onari's explosion.
Obviously pleased with himself, Onari glanced at Yu Wu. Her expression was amused, but he could still feel the anger inside her through their connection. She met his eyes, and after a few moments of unspoken communication, they both nodded.
Onari lowered his tails. Yu Wu stepped on, and the tails beneath her blurred in a split second. She was flung at her father with staggering speed. The flaming blade composed entirely of her internal turmoil was held straight in front of her.
Da Shuizhi barely had time to look up and gasp before he was skewered through the chest. The fires of Yu Wu's hurt, anger, and betrayal sunk deep into the center of the charred palm print. Da Shuizhi's insides boiled and burned as Yu Wu gazed coldly into her father's shocked eyes.
Da Shuizhi couldn't even force his body to move. His fingers didn't even twitch as his lifeblood and cultivation was used as fuel for his daughter's inner fire. His skin shriveled and cracked as he burned to a crisp from the inside.
Many emotions flashed across his face. As the light finally faded from his eyes, Yu Wu realized that her father only felt one thing. He didn't regret any of his actions or choices. He didn't regret how he had raised, neglected, and used her. He didn't even feel pride that she had surpassed him.
No, the only thing the leech known as Da Shuizhi felt before his death was disappointment that he had to die at all. Even in his last moments with his daughter staring him in the eye, there wasn't a single thought for anyone but himself within his mind.
Yu Wu's emotions flared. Her manifested sword flared with them, burning her father's body to ash in an instant. Her eyes lingered on the ashes as she stood there. The sword in her hand slowly disappeared into smoke.
Onari walked up behind her and embraced her. He flooded their connection with support. They stood like that for a long time as Onari helped Yu Wu process everything that had happened.
Without the soul-deep connection she now shared with Onari, a Heart Demon would be all but guaranteed. Even with the connection, Yu Wu would still probably be haunted with trauma for the rest of her life. And she would still have to deal with the almost impossible task of moving on with her life after all of this.
The only thing keeping her from curling up in a ball and breaking down into tears was Onari's promise and reassurances that he would stand beside her throughout the entire process.