Not Mine, except for storyline. Part of a trilogy and thus intended to be read in order.

1
To Not Deny

"No, no, no, no, no," Kuroba Kaito didn't even realize the low chant escaping him as he pressed rhythmically down on the chest of someone who had become an intrinsic part of his world. In full night-work uniform, he was anything but Kid's usual calm, suave self.

Because Tantei-kun had changed, screaming and growing and maybe become the self he'd been fighting to get back to, but had gone still (too still, not breathing-!) and Kaito had shoved back panicked grief in an attempt to save-

He didn't know how long he'd been doing CPR. His arms were shaking with exhaustion, his breath short and heavy, lips forming denials that he wasn't even aware of.

He'd known his tiny Tantei-kun wasn't Edogawa Conan, known who he was and what he was fighting, known also that the detective-in-hiding had come to see their little face-offs at heists as a reprieve from his daily life. Known they worked well together, having faced down far more dangerous criminals as a unit and, somewhere along the line, he'd started to look forward to his encounters with Tantei-kun.

Heists were more fun when he was there, more challenging, and Kaito had to think and react when the Taskforce (or even Hakuba) only had him having to act. That anticipation, that 'look, a challenge!' feeling had only grown stronger with each face-off, and after a while, seeing sharp blue eyes half-shrouded by flat glass had started to send a thrill of happiness (elation) through him every time he saw them.

He knew Kudo Shinichi had Mouri Ran, and if chases in moonlight and moments of terror against people who would happily kill them were all he would be granted, he would (he had) gladly take them. He'd be the reprieve from all the horror, the one who gave Tantei-kun something that made him think without making him think of blood and death and grief.

Mouri Ran's would one day be the shoulder to support, and he could, would, accept that.

Because Tantei-kun wasn't a jewel to be stolen. He was so much more precious than that, and Kaito wanted to see him happy.

But this—this was the terror of every nightmare he'd ever had multiplied and made real. This was horror that was sinking into his bones, his soul, and he wasn't going to give up.

But his arms were giving out and Shinichi was dead under his hands, body limp and far too still, and the monocle fell from his eye to clatter on the floor, weighted by tears he hadn't realized he was shedding.

His arms caved and he collapsed forward across Shinichi's chest with a choked sob, shaking, and he couldn't...

"Please, please, don't do this, Tantei-kun," he managed through grief like an ocean abyss, cracking into his soul as dark and heavy and cold as the deepest waters.

But Tantei-kun didn't respond, body lax and still warm from the fever-heat that had burned and taken as Kaito struggled to gather him into his own arms, and Kaito couldn't steal from Izanami* no matter how much he wanted to. He couldn't trade, either, though he would have; would have done anything, given anything, traded his life and his father's legacy, if only it would give Shinichi a chance at the life he should have had—

—but that was it, wasn't it? Shinichi had come to him, waited and lowered his own chance of survival, just because he wanted to tell Kid 'thank you'. But Kaito wasn't Kid, not really, he was only a shadow of his father's memory and right then he wasn't even that. And Shinichi had died in his arms, died screaming, and-and-and the door that he hadn't remembered to lock through choking fear on seeing the pill Tantei-kun had been carrying (careless, meaningless now, because he didn't care if he got caught, not anymore) opened behind him, slow footsteps (two sets, one that of a strangely light-footed child and the other—the other barely heard at all) making their way closer before stopping.

A voice, resigned and heavy, a voice he knew as that of Tantei-kun's mini-scientist friend, and he couldn't bring himself to care that she and whoever had come with her saw him so broken. What did reputation matter, with Shinichi lying dead in his arms?

Frantic, grief-shattered confusion shifted through him, and he didn't look up, couldn't, because he couldn't bear to see the truth of Shinichi's death reflected back again in other eyes.

The truth. The one thing Shinichi had always so staunchly stood by, even when having to live a lie, never lying to himself. Kaito hated it, hated it with a fury and passion greater than he'd ever hated anything, that truth. But Shinichi's very name wouldn't let him hide from it, deny it, and there was only grief and hollow, aching, hateful rage.

Not at Haibara Ai, who had done all she could, but at the ones who had started this, the shadowy group that had forced poison down his Tantei-kun's throat years before.

Whether they were the same people who had killed his father or not, he would not rest until they paid. Tantei-kun's Crows would find that doves were not so helpless as they seemed.

But—why had Tantei-kun come to him?

xxxx

*Izanami was a goddess of creation originally, but ended up as a permanent resident of the underworld after dying and eating food cooked there. The full story is more complicated, including her husband and a few others, but the gist of it is she became a vengeful hell-goddess.