Jesper knew the exact minute he realized Kaz was in love with Inej - and it was in the middle of a firefight. He reckoned he knew well before Kaz did. It was hard to acknowledge things you'd locked down for so long, and Kaz was a vault in more than a couple of ways. One of her knives had whizzed through the air, so close it almost sliced off a button on his coat, before it took out a Dime Lion that had been lurking behind Kaz. She moved out of the shadows and Kaz had huffed,
"Took you long enough."
"Maybe stick to the plan next time," she'd sassed back.
And as Jesper had created some suppressing fire, so the three of them could escape, he realized in that exact moment that he'd been usurped.
After that, it didn't take much more thought to reckon Kaz had fallen in love with Inej the moment he'd seen her. And it constantly made Jesper want to laugh out loud when he'd catch Kaz stare a second too long or get that exasperated face when she'd best him in their near-constant verbal sparring.
He had wondered. Everyone did. Kaz just appeared with her one day and had called him into his office. His instructions had been brief - this is Inej, find her some proper clothes and keep an eye on her. He'd shut the door on both of them and Jesper remembered the sound of the bells on her costume shaking with her shiver. When he'd glanced down at her he couldn't tell if it was because she was cold in that ridiculous outfit or because she was terrified she'd made a horrible mistake.
"Don't worry love," he'd reassured, "he's mean to everyone."
The truth of the matter was Inej was only the second person Kaz had hand-picked to be a part of his inner circle. He would know - he was the first. Sure every Dreg in the Crow Club liked to boast that they were "in" with Kaz but Jesper saw through the illusion of it all. The meticulous way Kaz kept track of every other Dreg - calculating, strategizing, planning. Everyone else thought they were in favor because he'd give them tasks, jobs, lies decorated as truths designed to be spread so he could suss out threats. Kaz didn't look at him and Inej like that. And he knew it was because he trusted them and only them. And then one day he trusted her more.
He wasn't mad. There were still plenty of things he didn't tell Inej. Jobs Kaz only gave to him. Jokes and memories only they shared. He had been Kaz's right-hand man for a long time before Inej had snuck into his shadow. Now he was Kaz's left-hand man and that was still a powerful place to be. For a man most people truly believed had no soul it always struck Jesper as fittingly hilarious that Kaz had fallen hard for someone as pious as Inej. But he supposed love was always a hilarious surprise. Always showing up when you least expected it, in people you would have never thought would be in your life in the first place. That's what made all their long stares they thought no one would notice the most endearing to Jesper. One day someone would stare at him as they did for each other - as his parents had. But until then he'd have his fun by provoking a demon and a ghost to keep trying to pretend they wouldn't die for each other all over again.