#primal mentality

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Shinsou creeps in after Denki one night, shoulders hunched and expression wary. He looks like he's completely out of his element, like he's walking into a minefield, and when Katsuki looms in front of him, he watches the other boy reel back like he's expecting to get punched.

Before he can open his mouth to sling shit, before he can even attempt to gain his bearings, Katsuki growls. Loudly. It's wordless and animalistic, an Alpha wolf squaring off against an intruder. Shinsou falters, taking a slow step back, and Katsuki matches him with a step forward. He growls again, lower, deeper -- closer to a snarl when those defiant violet eyes lock on him and the other teenager instinctively (thoughtlessly) tilts his chin down just enough to protect his throat.

Behind Katsuki, Denki is shifting anxiously, soft little whines giving away his distress. Shinsou fixates on him and moves to step around Katsuki, ignoring him in favor of soothing the omega.

Katsuki's bark is loud and sharp. His teeth snap shut barely an inch from Shinsou's cheek, and the other boy stumbles sideways, anger flaring in his eyes. He growls at Katsuki, cutting himself off and blinking in surprise. Katsuki's grin is wide and wolfish, his teeth bared as he stalks closer.

Shinsou holds his ground, but he's wavering. He knows what this is -- Denki's already told him, because Katsuki encouraged him to. If he wants to come, if he wants to join, he has to know what he's walking into. That was Katsuki's only stipulation.

He's been able to sniff out an Alpha personality since he was three. He knew what Shinsou was the moment he met him, and this is Katsuki's pack. This is his territory. Either Shinsou fights him for rights, or he submits and accepts that Katsuki leads this group.

Shinsou submits. Katsuki can see the humanity dim in his eyes; watches the bright, feral gleam of a predator unfold. His rumble is closer to a purr, rough and feline, when he averts his eyes and offers Katsuki the vulnerable line of his jugular.

Satisfied, Katsuki crowds into his space and licks across his pulse point; knocks their heads together lightly and rubs his scent across Shinsou's face before retreating. The panther's scent will blend with the rest of the pack-scent in time. He'll become one of them, and only absolute betrayal or his own decision will ever change that.

Once he steps back, the rest of the pack flows forward around him to welcome their newest member. Shinsou looks stunned at first, but slowly, with each new scenting, he relaxes until he's almost smiling.

"So," Katsuki rumbles, letting the others herd Shinsou toward the couches while he follows behind them, his shoulders relaxed and his mood content. "What do you want to know, Shinsou?"

Curled up on the couch with Denki on one side and Sato on the other, Shinsou looks up from where Kirishima's propped his chin on his knee and meets Katsuki's amused, indulgent stare.

"Everything," he says. "I want to know... everything."

Rumbling, Katsuki leans against the back of Shoji's chair and rests his chin on the tall boy's head. Deku looks up at him from his spot between Shoji's legs, scarred fingers carding through Iida's hair; the class rep's head is resting on his lap, his long body stretched out and tucked partially under the coffee table. Shinsou takes it all in as well, marveling at how absolutely tangled up in each other they all are. Eventually, his gaze returns to Katsuki, and he notices the way those violet eyes drop just enough that they aren't meeting his in a direct, challenging stare.