Fate's Slave - Shadow Slave X Honkai Star Rail

Kafka broke the lock without warning.

She twisted her wrist and let the pressure collapse, disengaging in a smooth motion that left Sunny’s counterforce cutting nothing but air. She stepped back lightly, magenta blade lowering a fraction as if she were reassessing rather than retreating.

Then she disappeared.

The rooftop cracked where she had stood, stone splintering outward a heartbeat after she was already gone. Sunny’s shadow sense screamed, instincts flaring as his body reacted before thought could catch up. He raised Hail Sorrow just in time.

A streak of magenta tore across his vision, and steel collided with steel in a violent flash. Sunny was sent skidding across the rooftop, boots carving deep trenches through reinforced plating as he fought to stay upright.

Kafka did not slow.

She was on him again immediately, blade flashing in a relentless cascade of cuts that left no space to breathe. Each strike came from a different angle, each one perfectly placed, forcing Sunny to parry, deflect, or evade on pure reflex alone. There was no rhythm to exploit, no pattern to memorize.

This was not a duel. It was instruction delivered through violence.

If Kafka had been any lesser Transcendent, Sunny might have had room to adapt. If she had been anything below that, the opening exchange would have revealed flaws to exploit.

Instead, he understood something far more unsettling.

If Kafka had been serious about killing him, this fight would already be over.

The realization settled into his bones as her blade skimmed past his throat. Sunny twisted, Hail Sorrow snapping up just in time to catch the strike. Sparks exploded as magenta light scraped against absolute black, the impact shuddering through his arms and rattling his spine. Before he could recover, Kafka’s foot slammed into his ribs, launching him backward into a ventilation structure that folded like thin foil.

He rolled, barely regaining his footing before another slash descended from above. He blocked again. The rooftop groaned beneath them.

Sunny was strong.

Stronger than most Masters.

His Divine Aspect allowed him to form more than a single Core, a privilege denied to ordinary Awakened. Three Shadow Cores burned within him, each one feeding directly into his Dormant Ability.

Three shadows overlapped his form now, indistinct silhouettes perfectly aligned with his body. They were not separate entities. They were layered manifestations of himself, each doubling his base strength.

Four times his normal output.

And his normal was already far beyond human limits.

That put him on par with four Ascended Demons stacked on top of eachother, barring only the biological monstrosities that made such creatures truly terrifying.

And still, it barely mattered.

Kafka’s blade whistled past his shoulder, then his knee, then his neck again, each attack forcing him into tighter margins. The difference in Rank was undeniable. A Saint existed on a level where hesitation simply did not exist.

Sunny did not believe she was trying to kill him.

That belief anchored him, kept panic from taking root even as the disparity became painfully clear. Capturing Kafka was impossible. The very idea bordered on absurdity. It would be harder than killing her, assuming killing her was even within the realm of possibility.

So he adjusted his objective:

Survive.

That goal alone became precarious the moment Kafka began to fully utilize her webs.

Threads snapped into existence around him, anchoring to nearby structures as Kafka zipped through open air with terrifying speed. She attacked from above, below, and behind, using momentum to amplify every strike. Sunny’s shadow sense blared continuously, warnings overlapping as his body moved faster than conscious thought.

Sunny dissolved into darkness cast by a fractured wall, slipping into the thin space between light and absence. The noise of battle dulled instantly, pressure easing as he existed in the cool, silent in-between.

He did not summon his Shadow Creatures.

Saint, Serpent, and Nightmare remained sealed in his Soul Sea. Sunny knew better. Kafka could dismantle them quickly, perhaps even casually, and their loss would cost him far more than they could buy him.

He emerged again several meters away.

Kafka was already there.

Her blade cut toward his head, and Sunny ducked, shadows reinforcing his movement as he slid beneath the strike and retaliated with a wide horizontal slash. Kafka twisted away, the edge missing her by a breath as she landed on a nearby ledge.

Steel rang again and again, thunder echoing across Stargazer Navalia as debris rained into the chaos below. Sunny was driven back repeatedly, forced into defense as Kafka pressed her advantage with relentless precision.

Then she swung.

It was heavier than before, a downward strike loaded with intent and momentum. Sunny met it head-on, shadows surging as he braced, but the force was overwhelming. The rooftop shattered outright beneath him, and he was launched off the building, sent spinning into open air.

Exactly as planned.

He twisted mid-fall, shadows hidden under his sleeves stretching outward from his body. They solidified instantly, tendrils snapping outward and anchoring to surrounding structures. Essence poured into the constructs, hardening them into a living grappling hook.

The shadows pulled.

Sunny’s trajectory snapped sideways, momentum redirected as he swung through the air, releasing and reanchoring in rapid succession as he fled the kill zone.

And Kafka was already besides him, swinging easily on her own string.

”It’s not nice to steal someone else’s flow.”

Sunny barely had time to process the words before her foot connected with his side.

He was sent flying again.

This time, he did not resist. The instant he struck a surface, his body dissolved into shadow, turning intangible as he sank into darkness beneath a collapsed crane. The force passed harmlessly through him, the structure detonating where he had been.

He remained there for a heartbeat.

Sunny turned his awareness inward.

His Shadow Essence reserves were holding far better than expected. More than that, the quality was exceptional, refined and potent, enhanced by his Attribute, [Essence of Divinity]. In purity, it was approaching the level of a Saint’s.

The quantity was even more absurd.

As someone with multiple Cores, Sunny’s reserves surpassed those of any normal Awakened by a wide margin. He could afford excess. He could pour Essence into Shadow Step to cross the entire Navalia in less than a fraction of a second. He could sustain Shadow Manifestation for far longer, as well. Of course, he had been strengthening his body with his exquisite Essence control, with no limit to how much he could pump. Unfortunately, there was a point where efficiency would drop...

’...Input... reflects output?’

It applied to everything. More distance crossed, stronger and more distinct shadow constructs, and even greater strength.

Then his thoughts drifted elsewhere.

To his Shadow Creatures.

They were summoned with the minimum required Essence, calibrated to their Rank and Class.

But shadows were mutable.

Ever-changing.

What would happen if he ignored the minimum and poured far more Essence into the summon?

Sunny stepped out of the shadows.

He reappeared atop a shattered support beam, standing tall amid destruction. Kafka was already facing him, perched lightly on a web stretched between structures, blade resting against her shoulder.

She tilted her head.

”What are you planning now?”

Sunny met her gaze, shadows coiling tightly around his feet.

”Saint.”