/Slightly altered the events of how Killua found Gon after the battle with Pitou... then again, HunterXHunter wasn't Omegaverse, either, so I'm sure you won't mind.../

Chapter 2: A Shock to the System

"Often, it's not about becoming a new person, but becoming the person you were meant to be, and already are, but don't know how to be."
― Heath L. Buckmaster

Several Weeks Before

Though he knew Gon was set on facing Pitou alone and had agreed to stay behind, Killua could not suppress the panic welling up inside of him, a roaring and crackling electric tension that made his hair stand on end. He stood, pondering and fidgeting-a nervous habit Illumi had forced him to repress in a previous life, but he was long past caring about stilling his presence.

Someone was addressing him, but he could barely hear; his eardrums were buzzing with the undercurrent of anxiety-generated electricity. Through the static he made out Gon's name. Forcing himself to focus, Killua realized one of Shaiapouf's pixie-sized clones had appeared to gleefully announce Gon's impending demise at the hands of Neferpitou.

Killua became lightning incarnate, moving instinctively in the direction of the forest. Blinding light erupted from the thick core of the black trees. Heart racing, Killlua tripled his electricity-enhanced momentum, fallen twigs and other woodland detritus sparking as they were kicked up in the powerful wake of his movements.

While yet several tree lengths from the clearing, a powerful smell accosted Killua's nostrils. He stopped short so suddenly he nearly fell. He clasped his hands to his knees as he heaved, but felt a sudden sharp pain; he glanced down, realizing his fingernails had instinctively lengthened into his assassin's claws.

As he fought his ingrained instincts to flee from the unknown scent, Killua was reminded of one muggy summer when Father, Grandfather, and Illumi had all gotten food poisoning at some state official's banquet and thrown up their hormone suppressants and scent inhibitors (though proud of their Alpha status, the Zoldyck elders knew that the nature of assassin work often required one to be scentless so as to avoid detection). The thick, windless days combined with the pungent odor of the three thoroughbred Alphas to produce a thick miasma of hormones that caused even Mike to whine in discomfort.

For those few uncomfortable days, the Beta servants plugged their noses to stay unaffected while performing their daily duties. Even the stoic Goteau, too proud to show weakness to his employers, couldn't hide a slight wrinkle in his nose at the overbearing stench of Alpha as he walked the corridors of the Zoldyck estate.

Only his mother Kikyo had seemed to enjoy the smell, fanning herself in ecstasy with a handkerchief dipped in the sweat of all three Alphas as she reclined on a pillowy divan. In retrospect, Killua could never say whether his sado-masochistic mother actually enjoyed the scent itself or whether she simply enjoyed the torture of it.

This scent, however-this was quite easily the most powerful scent of Alpha he had ever come across. When the abrupt shock to his system passed, however, he had to admit the scent wasn't terrible. It was simply as if someone had over-eagerly applied a concentrated cologne; once the scent dissipated, it became tolerable. Perhaps, more than tolerable.

A large, muscled stranger lay in the clearing, drained almost completely of life energy and gasping shallowly. Though Killua had not witnessed Gon's incredible physical transformation, he identified his friend immediately.

The white-haired assassin dashed past the discarded, pulpy remains of Chimera Ant and knelt next to his injured friend. Killua hesitated to touch Gon as he visually examined him, fearing that any residual electricity he carried could disrupt the weak rhythm of Gon's heart. His beautiful little Gon had disappeared, replaced by this big, hulking, unconscious Alpha male. Killua's heart clenched as he spotted Gon's severed arm several feet away. Alluka would help heal it, restore his friend to his original form.

But there was one thing even Alluka could not fix. Dimly, Killua realized his eyes were welling up. To see his friend in such a state, physically enervated to the brink of death- but it was more than that, though Killua knew he was selfish to wish Gon had presented differently. His heart literally ached at the unfairness of it, tender dreams of his lovely little Omega shattered.

As Killua rose to collect the limb, a deep rumble of discomfort emitted from Gon's chest. Killua responded with a plaintive whine before he could stop himself. Get it together, Killua, he chided himself. Illumi would most certainly have disapproved. His older brother had labored for years teaching Killua to minimize any and all noises under duress, whether cries of pain or the instinctual rumblings, purrs, and other noises that could jeopardize the status of a mission (which often required one to be noiseless, even under extreme torture). And yet, for all his years of ingrained training, Killua had positively whined at the first noise of this Alpha. What does that mean?, his clever mind wondered, racing to fill in the gaps. Is this a sign of reaching maturity as well?

His attention was diverted by movement from Gon, whose nostrils were flaring wildly. Killua felt a sudden pooling, pleasant warmth low in his belly, and he bared his teeth at Gon. Though he had slipped into unconsciousness, this Alpha beast was scenting Killua as if he was prey. Gon's own pheromones, far from abating, had strengthened in intensity; Killua could clearly smell the heady musk, the dark, fertile earth and oak. It was a smell that was quickly growing on him; Killua found himself breathing deeply to better fill his lungs with that distinctive scent. Killua wondered if perhaps Gon's natural proclivity as an Enhancer strengthened his musk. Probably.

Suddenly, Gon's eyes flew open, and Killua nearly flinched at the intensity of the unseeing stare. It was like locking eyes with Nanuka. Gon's eyes were no longer a warm, responsive brown, but had become a depthless black. As he met eyes with Gon's inner beast, the warmth in his stomach became a slicing, excruciating pain, and Killua dropped to his knees, clenching his gut. Darkness outlined his vision and he closed his eyes as a current of pain flared through him, scaldingly, blindingly hot.

What-?! The uncomfortable, tacky substance smearing down his thighs answered his question before it was even fully asked in his mind.

The overwhelming pheromones of this Alpha Enhancer had somehow triggered a response from Killua's own dormant system, forcing him over the cusp of sexual maturity just as certainly as Wing-san had opened his pores to accept Nen.

Killua Zoldyck, heir to the Zoldyck estate, bred from a centuries-old line of thoroughbred Alphas, expected to be the most powerful assassin of all time, had somehow presented Omega.

Though he was usually able to maintain a clear head under extreme duress, this particular pain rendered him thoughtless. Killua dropped to all fours, gasping and heaving as pain wrenched through his system. Each of his internal organs felt as if they were being pressed through one of Milluki's devious torture devices. He should be able to think-needed to think- of a way to get Gon and himself to safety. Nothing came. His thoughts were clogged by pain, drowning in disbelief, irrational.

Black spots fringed at his vision, gamboling and spinning in and out of focus. Unconsciousness beckoned with a crooked finger. The trees were falling-no, he was falling, his arms useless like a fallen house of cards, his jaw striking the ground sharply enough to short-circuit his brain. A single, clear thought floated into view even as he lost awareness.

Mother is going to lose her shit.