When he was a child, he liked to play with fire.
Well. Honestly? Playing with fire is the reason he became a firefighter. Why go down the prison-jail road when you can make it seem like a heroic, caring, selfless thing? People are easy to fool: they always want to believe the best of you. Even the ones that should know better.
That's fun, too, playing with people. After all, it's another form of playing with fire—a figurative one: Hello, I'm the hero here to save you, instead of Hello, I like the smell of your burning flesh and those oozing blisters on your face and that oh-so-terrified look in your eyes.
He doesn't get how normal people work; he never has—but shit, he can fake it, and fake it real good, 'cause nobody sees it.
Nobody sees him.
And that's a thrill, hiding there in plain sight, there among all those fucking heroes, pretending to be one of them.
Pretending he doesn't want to see them burn. Doesn't want to see them twist and scream with their flesh coming off in bloody charred patches under his hands, doesn't want sweet, inextinguishable steel-blue flames to lick at their bared bones. Doesn't fantasize about the ones that died, the bodies they pull out and the ones he's known alive, walking and talking and thinking he was so tame.
Darden had been nothing special until he burnt. But oh, how much Kevin had loved that thrill, seeing the smoke get sucked upstairs and in that second, the look on Severide's face through their masks, the sheer, absolute terror in his voice. Terror of knowing what was inexorably happening and that his friend was up there—he'd frozen for a second and fuck if that hadn't been absolutely delightful: his fucking hero of a Lieutenant, freezing.
Kevin had hoped, in that same second, the flames might take him too, just a little, just a little burn or two on that too perfect face, because that would have made Severide breathtaking—but he'd had to settle for watching him grunt in pain landing on the floor, watching the devastated look in his eyes as they pulled Darden's satisfyingly crispy remains out of the blackened, dripping house: Severide had been as emotionally burnt as Darden had been physically, and Kevin hadn't known then which was the most fascinating, because there had been too much to see and not enough time to do it properly, especially not while controlling his own facial expression to have it stay an appropriate mimic of the others'.
He'd volunteered to help carry Darden to the ambulance to be able to look at him as much as he could before it drove off with him, and walking right behind Severide he'd seen his shaking slumped shoulders and thought that beautiful, too, the grief and the defeat, and so when Darden had disappeared, he'd clapped his Lieutenant gently on the back, like the Truck guys crowding around theirs, playing friendly and sympathetic with Tony and Capp on either sides, and he'd watched Severide's blue, blue eyes burn—burn like those sweet, inextinguishable steel-blue flames that are always the hottest, that always do the most damage.
He'd lost his breath, at how sublime that had been.
They'd filled with tears, eventually, Severide's burning eyes—tears and rage, and Severide had launched himself at Casey, and they'd all scrambled to separate them, nothing but a mess of screams and sobs and flailing limbs, ignored shouted orders and struggling, tightly-coiled bodies, grief and anger and defeat—all matters of shattered normal things. Kevin had grabbed Severide's hips, snaked both arms around him and pulled with the others, had felt Severide's whole muscled, tense frame violently squirm against his through their turnout gear, and had been surprised to find it as much of a turn-on as the best destructive fire.
He'd let go in shock, pretended he's gotten a bad kick and had only grabbed him again from less close, had helped Capp wrestle him down instead of doing it himself. But the memory had stuck.
Now, really, it's his favorite fantasy: Kelly goddamn Severide, struggling in inevitable defeat, hurting and breaking and burning, inside and out, mind and body, with no end ever in sight. Those eyes, those sweet, inextinguishable steel-blue-flames eyes, looking at nobody else—unable to look at anybody else, not the parade of trollops, that bitchy dyke of Shay, or that fucking blond fag of Casey.
It keeps Kevin warm at night.
It keeps him warm during the day too, every time he's on shift: like any fire, you gotta tease it to keep it burning, and he teases that sweet, sublime look in Severide's eyes with seemingly innocent little comments, small awkward-looking reminders, pretend incompetence. Subtly manipulates Capp and Tony into the same things without them realizing, and watches in carefully-concealed delight as his Lieutenant breaks a tiny little more every time, and never, ever asks for anybody's help. Because he's Kelly goddamn Severide, hard-ass Lieutenant of the best Squad in the city, and he's a tough-as-nails manly bastard.
Kevin loves that about him too, because that makes it better: even nails burn eventually, turn into melted unrecognizable garbage—but at such high temperatures, it's a gratifyingly thrilling challenge to get them there.
Something will have to give at some point, he knows. He can't hide forever, can't keep just watching and teasing, and simply fantasize about the blast: it's enough for now, but sooner or later it won't be. Sooner or later, he'll have to show his face—show himself. His real self, the monster that lurks under the good-boy mask.
And he cannot wait to see the shattering, burning look in his Lieutenant's fire-blue eyes, when Severide finally realizes exactly what kind of horrifying, sharp-teethed predator he's been harboring in his beloved team all this time.
Because really, Kevin's always liked to play with fire. And Lieutenant Kelly fucking Severide? Lieutenant Kelly fucking Severide is his goddamn fire.
And his alone—sooner or later, he'll make sure of that. Make sure nobody else has his Lieutenant's attention.
In the meantime, however, he'll just keep smiling in his face like the good boy he's not.