The Blood Oath of a Father: Cursed to Be Her Brother’s Blade

Kun Buyu had finally spoken the truth, yet Wan Ling could not, would not, accept it.

“Why…” Her lips were cracked, her voice hoarse. “Why tell me now? Wouldn’t it have been better to keep it hidden forever? Why reveal it now—why now!” She asked again and again, not knowing how many times she had repeated herself, not realizing that with each repetition her voice trembled more violently.

“Because I will not live much longer.” Kun Buyu pressed a hand to his chest. Blood seeped through his robes, dark and glistening even in the faint firelight of night. “There are things I must do while I still have the strength. Once I die, it will be too late.” Then, strangely, he smiled with fatherly tenderness. “In truth, I have always thought of you as a daughter. For instance—every time Hong’er chased you and called you ‘sister,’ I never stopped him.”

Wan Ling did not even hear those final words. Her entire mind clung to that single phrase: I thought of you as a daughter.

She wanted to scream at him—If you truly saw me as a daughter, why did you mark me as a slave? Why did you make me cook and wash, wait upon your family, live in chains? Why, when assassins struck and you fled for your life, did you carry only Kun Hong on your shoulders, leaving me behind?

She wanted to ask. But no words came out. The firewood crackled and spat, sparks rising into the cold night sky.

“Do you remember what you said earlier?” Kun Buyu’s voice was low. “That you would protect Kun Hong at all costs. Remember that.”

“I remember.”

“Then swear it.”

“What?” Wan Ling jolted.

“Swear it.” Kun Buyu’s eyes, in the dark, became a bottomless whirlpool, as if they could swallow the night itself. Wind whispered around them. Not far beyond lay the borders of Nan Chuan—a small country, rich in soil and gentle in its ways. In that place, even two orphaned children would not starve.

“I will say a line, and you will repeat it after me.”

“…Yes.”

Kun Buyu’s voice rolled like distant thunder:

“I, Wan Ling, swear to give my life, at any cost, to protect Kun Hong.
I will raise him to manhood, return him to Beiji, and see him claim the seat of Grand Priest.
I vow to turn my blood and my soul into a blade in his hand, to cut down every obstacle, to destroy every enemy.”

How cruel a vow. To pledge one’s blood, one’s soul, one’s very freedom—to become nothing but a weapon, a killing blade, for another’s sake. Kun Buyu spoke it gently, but in truth, he was condemning Wan Ling to eternal torment, grinding her bones to dust, casting her into an endless abyss from which she could never return.

“No!” Her voice broke. “I won’t! I won’t—”

Before she could finish, his hand clamped around her throat.

His eyes burned scarlet. “You have no choice. You will swear. Wan Ling, do not blame me for cruelty. I have seen through you—you are selfish, just as I am. Once I die, you will abandon Kun Hong, chasing your own freedom. I cannot allow it. I must leave him a future.”

She choked, gasping for breath. Her vision blurred, tears gathering before spilling hot down her face. She trembled violently, broken syllables spilling from her lips. “…Master… Master…”

Kun Buyu turned his face away. He could not bear to look at her.

Finally, Wan Ling sobbed out the word: “Father.”

His body shuddered, but he still did not turn.

“Father, I swear.”

His grip loosened. She collapsed to the ground, coughing.

And then she repeated the dreadful vow. Every word, every syllable, carved on the tip of her tongue. When she was done, Kun Buyu reached into his robes and drew out a blood-red moth. With a light flick of his fingers, the creature circled once in the air before plunging straight into Wan Ling’s left eye.

“Ahhh—!” she screamed, clutching her face, rolling in the dirt.

“This is the Soul Vessel,” Kun Buyu said between ragged breaths. “Your vow will now bind you. Break it, and the Vessel will grow inside you, day by day. It will devour your soul, then your flesh, and in the end cast you into the deepest hell, never to know rebirth.” His lips curved into a grim smile. “That is the safeguard I leave for Kun Hong. Wan Ling, do not blame me.”

With those words, he forced himself to his feet. “There is another rabbit here. Eat it in the morning, then cross into Nan Chuan. Tonight, I will clear the path ahead.”

And into the night he vanished.

Wan Ling lay on the ground, face pressed into the grit. Fine grains of sand filled her nose, clung to her cheeks and hair. She said nothing, only watched his back retreating into the darkness.

“I understand.” At last, when he was far away, she whispered, “I will protect Kun Hong. I will be his killing blade, his ladder across the clouds, his stepping stone—until the Kun clan rises again.”

But she did not say “our Kun clan.” She said “your Kun clan.”

All of this, Gongsun Bai and I witnessed from the shadows. For Kun Hong, the child at the center, knew nothing.

All he knew was that when he woke the next morning, his father was gone.

“Where is my father?” he asked for the fourth time.

Wan Ling gave no answer. She only tore a rabbit leg from the carcass and stuffed it into her mouth. Never before had she dared to take the fattest, tenderest part for herself. She devoured all four legs, leaving Kun Hong only the skinny backbone. He did not complain.

When he was full, Wan Ling wrapped the leftovers and tied them into her bundle.

“Let’s go.”

“Go where?”

She pointed south. The fields of Nan Chuan spread faintly on the horizon. “There.”

Kun Hong shook his head. “Not without Father.”

“He’s not coming back,” Wan Ling said flatly, stamping out the fire.

“He’ll come back. I’ll wait for him—” Kun Hong sat stubbornly on the ground, refusing to move.

“Suit yourself.” Wan Ling sneered, turned, and strode toward the cave mouth. But after only a few steps, she stumbled with a cry. Agony flared in her left eye, as though fire had seared straight into it. She fell, clutching her face, tears streaming down her cheeks.

The curse. The proof of the vow. She understood now: if she ever tried to abandon Kun Hong, or even so much as wished him harm, the hidden bomb within her eye would erupt, scourging her with pain.

When the agony finally ebbed, she drew a deep, shuddering breath. Then she marched back into the cave and kicked Kun Hong hard in the side.

“He’s dead!” she snarled.

And indeed, Kun Buyu was dead.

The night before, after binding Wan Ling with the Soul Vessel, he had gone alone to the enemy camp. One man against fifty. Even famed as he was, wounded as he was, he could not prevail. Soon the clash of steel rang from the west, flames lit the sky, and phantom moths swarmed to feast on spilled spirit.

An hour later, all fell silent.

The moths dispersed. The world grew quiet. Kun Buyu never returned.

Wan Ling needed no proof. She knew. He had died—and died horribly.

For years afterward, one question haunted Kun Hong’s heart: Why? Why had Wan Ling changed so suddenly in a single night?

Once, she had been cold, yes—but still gentle with him. He remembered vividly how she had taught him illusion, patiently repeating each step no matter how slow he was. Her hands had guided his. Her voice had been soft.

Now she was harsh, unpredictable, quick to anger. She scolded him, snapped at him, treated him like a burden.

But—she never abandoned him.

Distances deceive. Though Nan Chuan looked near, the road was long. They walked until their feet blistered and bled. Wan Ling bore every bundle on her thin shoulders, while Kun Hong carried nothing. Still, he faltered, unused to hardship after a childhood of luxury.

On the third day, a sharp branch pierced through his worn shoe, stabbing into the sole of his foot. He collapsed, rolling in the dirt, weeping in pain. Wan Ling snapped at him impatiently: “Useless boy!”

They rested in a cave. The next day, she fashioned a crutch from a branch. Then, without a word, she bent down, lifted him onto her back, and carried him onward.

Kun Hong flushed with shame. Though injured, he was still a boy—how could he let a girl carry him? He begged her to put him down.

Wan Ling ignored him, leaning on her crutch and trudging forward.

When his chatter grew too much, she cut him off, her voice sharp as ice.

“So what if I carry you? You’re the master. I’m the slave. I was born to serve you for life.”

Kun Hong’s face turned scarlet. “I never thought of you as a slave!”

Wan Ling gave a cold laugh. From head to toe, she radiated frost.

“Does that matter? Does your opinion change anything?”

And Kun Hong was left speechless.