My Sister Stole My Mate, And I Let Her

Chapter 504: Chapter 504 FULL ACCESS

SERAPHINA’S POV

In hindsight, it probably wasn’t a good idea to tease a psychotic lunatic backed by an unknown, powerful force.

Malachar, whoever he was, was more than willing to grant Catherine full access.

The blue veins of light embedded in the walls flared brighter, then steadier, like arteries hit by a stronger pulse. The ritual structure beneath us—carved stone, blackened metal, and sigils—began to hum in response.

And Catherine...

The difference was immediate.

The oppressive presence that bled into the room no longer felt like something she was invoking.

It felt like something she was wearing—no, not wearing, hosting.

The air around her darkened in a way that had nothing to do with light. It was as if the concept of shadow itself had gathered around her form and melded with it.

I recognized it instantly.

That same suffocating pressure from the void. That same invasive awareness that had spoken into my mind, offering me itself or death.

My stomach tightened.

So it wasn’t just that she served him.

She was now an extension of him.

Catherine lifted her head slowly, and the eyes that met mine weren’t hers.

They’d gone entirely black, and there was something layered behind them—hungry and deadly, like a predator looking through a window.

“You feel it, don’t you?” she said softly.

Her voice was still Catherine’s, but flattened at the edges, like it had been pressed through something too large for it to carry fully.

The darkness around her thickened, coiling through the chamber like living smoke.

I forced myself to stand straighter, even as the pressure in the room pressed against my skin and consciousness.

The power inside me stirred in response, but it was...sluggish now, as if something was interfering with my access to it.

Maybe I had used more than I knew to escape the dreamscape I had been trapped in. Maybe this new enemy was affecting it more than I realized.

Either way, my power felt dampened, as if I were no longer entitled to it in full.

Catherine noticed my struggle immediately, her eyes lighting with triumphant amusement.

“Oh,” she murmured, taking a step forward. “This is interesting.”

Another step.

“Performance issues?” she taunted.

I forced a grim smile. “Touché.”

I could feel it more clearly each second: the formation beneath us wasn’t just a structure. It was a system—a living network of siphoning conduits.

It was feeding Catherine and starving everything else.

Including me.

Catherine tilted her head, eyes glittering with delight as she watched me, clearly savoring the realization unfolding on my face.

"I bet you felt pretty special when you anchored to the moon, huh?" Catherine drawled, her voice softening into something indulgent.

“But you know something about the moon?” Her smile widened. “No matter how much power it boasts of, the light it shines is a reflection. Something borrowed. And borrowed things are never permanent.”

I scoffed. “You’re one to talk.”

She barked a short laugh. “Do you know what I find amusing about you, Sera?”

I didn’t answer, but she didn’t seem to need one.

“You think your resistance makes you different,” she continued. “You think struggling against the shape of your life makes you special.”

The darkness behind her shifted again, as if it were listening through her and agreeing.

“But all you’ve done is choose the worst possible version of yourself even when I offered you something better.”

My hands clenched into fists as I bristled at her words, the memory of the life she’d woven for me in the dream flashing in my mind.

“You never offered me anything,” I shot back. “You tried to reframe my reality. You fed me a lie gently wrapped around a chain.”

“And wasn’t it a beautiful life?" Catherine asked. "You had everything you could have ever wanted. You could have spent the rest of your life happy if you just stayed put.”

“No thanks.” I shook my head. "You wouldn’t know true happiness if it bitch slapped you in the face.”

She considered my words for a moment, then shrugged. "I’ve always found the pursuit of happiness a foolish endeavor anyway. Much more fruitful to gather power.”

Then she moved without warning.

She crossed the space between us in an instant, and the first strike landed before I could brace for it.

I staggered backward as pain lanced through my chest, sharp and disorienting, as if something inside me had been grabbed and twisted out of alignment.

Catherine watched me stumble, her expression calm again, satisfied.

“I told you,” she said. “The moon only borrows light.”

She raised her hand, and the darkness around her coiled tighter.

“And the dark swallows everything.”

She struck again.

I barely managed to block it this time, forcing my silver energy outward in a defensive surge.

The collision sent a shockwave through the chamber, rippling across the ritual markings on the floor.

For a moment, I saw the system clearly.

The way the energy flowed from the walls, into the floor, into Catherine, and then outward again, like a loop feeding itself.

The chamber wasn’t just amplifying her; it was sustaining her like a battery.

If I kept trying to fight her directly, I would lose.

Not because she was stronger, but because the battlefield itself was rigged.

Catherine came at me again, relentless now, each strike faster than the last, each one pressing deeper against my resistance.

My silver energy flared instinctively in response, but it felt like trying to push against a tide that was being actively reinforced from beneath my feet.

It was time to do what I had been too emotional to do before.

Think.

I shifted backward, narrowly avoiding another strike, my boots scraping against the stone. My eyes flicked down for half a second.

The runes beneath us were not random.

They were directional. Flow-based.

Which meant—

My gaze snapped back up.

Catherine was already moving again, her face twisting with visible impatience.

“You’re adapting slower than I expected,” she said. “Perhaps I overestimated you after all.”

She shrugged. “Or perhaps this is simply what you are without borrowed power.”

I didn’t let her bait work, focusing as my mind worked through all the ways out.

If I couldn’t match her directly, I needed to break the system.

I let her next strike come closer than I should have.

At the last possible moment, I twisted aside and redirected the impact into the floor instead of my body.

The stone cracked, and the runes beneath it flickered.

In that instant, I saw it—the weak point in the loop.

Unfortunately, Catherine noticed it too.

“Oh.” She chuckled, her gaze darting to the floor. “How clever.”

She moved again, faster this time, forcing me to retreat another step.

But she wasn’t moving toward me.

She darted to the left, and panic flooded my chest as my eyes widened.

“No!” I gasped as Catherine reached for my mother.

She was still where Catherine had dumped her, her body half-cradled in broken stone.

“Stay away from her,” I hissed. “I won’t let you desecrate her like you did my father.”

Catherine paused, her mouth forming an ‘o’.

Then she threw her head back and laughed. “Oh, you silly little thing. You think she’s dead?”

My blood ran cold as Catherine leaned down and grabbed my mother by the neck, holding her body up against her chest.

My eyes widened when I saw her chest move, ever so slightly, as if the faintest trace of life still clung to her.

“She...she—”

“Oh, she’s still alive, sweetie,” Catherine cooed, gently stroking back her hair. “Still useful.”

A low growl built low in my throat as I charged.

I stopped short when Catherine tightened her grip around her throat.

“Ah-ah.” She shook her head. “I wouldn’t do that if I were you.”

The darkness around her shifted again, weaving around my mother’s unconscious form.

"Who knows," Catherine mused, "maybe if I stop her heart once and for all, the infernal block she placed on her power will dissipate."

My silver energy flared violently in tune with the spike in my anger, and for a split second, I lost focus on the formation entirely.

And Catherine struck.

The impact drove me back hard enough to skid across the stone, my vision flashing white at the edges.

She was already walking toward me again before I could recover.

“How about it?” she said. “I can continue dismantling you piece by piece, or you can reconsider the offer you were given earlier.”

I didn’t need her to clarify.

‘Accept me.’

My breathing tightened as I fought not to lose control as I had earlier.

Every instinct in me screamed to protect my mother, fury and desperation building until I nearly lashed out at Catherine, desperate to find a crack I could exploit.

But I knew that would be the beginning of the end.

If I lost my focus, if I couldn’t hack her system, I would lose everything.

Catherine raised her hand again, darkness gathering at her fingertips like a blade forming out of absence itself.

“Let’s see how long your resolve lasts,” she said softly. “I bet—”

The doors at the far end of the underground hall exploded inward, and stone shattered in a violent arc.

Despite everything, a relieved, almost giddy laugh burst out of me.

Because through the dust, Kieran stepped forward.