“Mine.” One word, a single syllable, that changed everything.
At first, Beyond hadn't known, hadn't understood, why he said it. Except he did.
Because when he first saw the Omega, all splayed pretty on his bed like he was lying in a coffin, a final resting image broken only by the tender rise and fall of his chest, some… thing had taken hold.
A feeling. Possessiveness. Like he had once felt, once felt burning for L Lawliet, his should-have-been Alpha.
As soon as it tumbled out of him, from where he crouched above the Omega, poised and with only his bare hands (Knives were wonderful yet impersonal tools; Beyond had wanted to rip out the throat of the Alpha-stealer himself), the Omega started awake.
Soft eyes stared into his, the air around them drenching in fear.
“Wh-who are you?” The voice came out pitched-high and squeaky; Beyond doubted he had enough air to scream for help.
“Mine.” Beyond repeated, to himself mostly. It felt strange. But it felt right. He was speaking some sort of truth, forgotten and anchient and oh so perfect. Something feral built within him at the look of fear on Light’s face.
“I said who are you??!” The voice increased in volume. “I-I'm gonna call my dad!”
“Shh, shh!” Beyond soothed, smoothing into a neutral stance and trying his best to pat comfortingly at Light’s thighs. The boy only flinched back in distress. “I'm an Omega like you, alright? Not some mean old Alpha here to… take advantage of you.” Something told Beyond he couldn't afford to be crude with the boy before him.
“Why the fuck are you here?” Light snarled, legs drawing out of reach of him. Beyond noticed with fascination how Light’s arms crossing only served to accentuate his chest.
“I…” That was a very good question. One Beyond did not have a very good answer for. “I was drawn to you.” Perhaps the boy would like flattery…
“I- what? Explain.” Light turned icy. An attempt to hide his fear.
“You know how sometimes Alphas get very strong and special feelings about Omegas? And how they sometimes get feelings like they need to… follow them?”
“But you're an Omega.” Something close to skepticism had entered Light’s tone. “That… All of the textbooks say that-”
“Well, not exactly.” Beyond winced at the look on Light's face.
“So you lied to me?” His voice rose.
“No. I'm not an Alpha.” Beyond’s eyes met Light’s.
“And you're not ‘exactly’ an Omega? So you're nonbinary?”
“You still lied to me.” Light’s eyes burned.
“You needed to calm down.” Beyond growled. He stalked forward, eyes trained on Light. With each step, Light shrank back, until he was pressed up against the wall. He placed his hands, one on each side of Light, on the wall.
“Please don't hurt me.” Light whimpered, his neck bending in submission. Rumbling deep in his throat, from somewhere he hadn't thought of as possible until then, he buried his face in Light’s scent gland.
Beyond didn't know what he was doing. He was supposed to have killed the boy minutes ago, supposed to have never have woken him up, and yet-
Beyond nuzzled the scent gland again, some newly ignited instinct taking over as he lapped long, wide strokes over the shivering boy. Wet slick pooled in his boxers at the scent.
“You taste so good…” he murmured, teeth biting down ever so gently-
“Please don't.” The boy, Light, his Light, whimpered. “I'm only seventeen! I'm too young to be mated!” Tears tracked his face.
Beyond pulled back. The boy was young, sure, but… “And let someone else have you? I'm not leaving without staking my claim.”
“Then do it somewhere where it's unnoticeable. Please.”
Beyond weighed his options, before nodding. “Pull down your pants.”
“You have a scent gland on your inner thigh, and if anyone gets close enough there to find out, I promise you that I will kill them.”
Light shakily pulled down his pajama pants.
Beyond took a moment to drink in the sight. Dark hairs covered Light’s mound, and he could already smell the slick pooling in his vagina. Carefully, he opened Light’s leg.
Nosing into his heated inner thigh, he licked softly, Light squirming slightly.
“The fuck are you-”
“It's so it won't hurt, dumbass.”
Light stopped squirming. Instead, he held stock-still, wincing only slightly when Beyond bit down.
As soon as Beyond’s face had pulled up, Light yanked up his pajamas.
“I'll let you sleep now.” Beyond murmured. Light said nothing as Beyond slipped out of the window.
As Light went about falling back into a fitful sleep, Beyond watched from his perch. His plans had just made a drastic change.