My sister's mate became mine after they stole my core

He chuckled lightly, eyes glinting with curiosity and something else I couldn't place. “You’re a straightforward woman. I admire that. So tell me—why didn’t you put up a fight and just came with me?”

I stared at him, taking my time as my eyes roamed over his seated frame. I didn’t respond. I should tread carefully and know what am entering before saying something that isn't needed to be said.

He stood up and stepped closer, his presence commanding, overwhelming even. He reached out and tilted my chin with two fingers, forcing me to meet his gaze. I hated the way my skin reacted, hated the tingling sensation that danced along my jawline. There was a pull—a bond I didn’t want—but I played along.

“I don’t want a mate,” he said coldly. “I don’t want love or anything messy. All I need is an heir. Give me that, and I’ll let you go. In return… what do you want?”

I hesitated. I needed to tread carefully. “Can you tell me why you don’t want a mate?”

A faint smile touched his lips. “Because I don’t believe in fate… or mates, or any of that nonsense.” Something flickered in his eyes—grief, maybe sorrow—but it vanished as quickly as it came.

There was something broken in him. Something like me.

“I want revenge,” I said bluntly.

His hand dropped from my chin as he turned away, walking back to his seat with a casual air. “I’ll give you the revenge you want,” he said without pause. “But I want no part in your past. Whatever happened to you doesn’t concern me. The revenge... I can assist with, if we strike a deal.”

I crossed my arms. “And how do I trust that deal?”

He chuckled, pulling open a drawer and taking out a clean sheet of parchment. “We’ll sign a contract and make a vow. We both know how sacred vows are.”

Even though my heart thundered in my chest, I pushed forward, knowing I had to ask the one question that could unravel everything. “Even if the person I want revenge on is… your true mate?”

That made him pause. He stared at me, the silence sharp and heavy, before speaking slowly. “It doesn’t matter to me,” he said. “All that matters is the heir.”

No hesitation. No guilt. Just cold practicality.

The room was silent and the only sound was the scratch of his pen moving across the paper. He wrote swiftly, confidently, like someone used to making deals with no emotion involved. When he was done, he handed it to me along with a pen.

I read it carefully. Everything was spelled out in brutal clarity. He would support me in taking down those who wronged me—no questions asked, no interference. In exchange, I would give him a child. An heir. Then I would walk away, never to return.

Simple. Cruel. Tempting.

But one question burned in my mind. Could I really walk away from my own child? A child created with purpose but no love? A child that would be his legacy… not mine?

“what if the baby is a girl?” I asked quietly.

He looked up and smirked. “That’s why the contract says an heir. We’ll keep trying until we get one.”

I wanted to slap the smugness off his face. But I held it in. I was here for revenge, not emotion.

Still, I placed the pen on the paper and signed my name. A single signature, but it marked the beginning of a war I was willing to fight.

As I finished, he spoke again, casually, like we were discussing dinner. “Which is why we should wed quickly and It shall be done five days a week.”

I blinked, confused. “What shall?”

“Sex,” he said flatly, not even flinching.

My face flushed hot. Of course—how else were we going to produce an heir?

“Five days?” I echoed, appalled.

“Why don't you just say all week?" I muttered bitterly.

He tilted his head, his tone dry. “Well, that’s fine by me. I don’t mind.”

I gritted my teeth. “Three days.”

He raised a brow. “Four.”

I narrowed my eyes. “Three.”

Were we really negotiating the number of times we’d have sex like it was a business transaction? Apparently, we were.

He shrugged. “Fine.”

He stood then, his posture shifting as if something weighty had settled between us. He lifted his hand solemnly. “It’s time we take our vow.”

His voice was steady, sure. “I, Alpha Dean Lucas, vow to help you get the revenge you seek, if you give me an heir.”

I closed my eyes, forcing back everything I felt, and whispered, “I, Becca Wilson, vow to give you an heir, provided you fulfill your oath to get me my revenge.”

He nodded once, firm. “It is done.”

And just like that, my fate was sealed—with the man who was never supposed to be mine.