It's far from the first time Sirius has seen Kieren bleed, but he's never seen so much of it all at once. Kieren buries his face in his shirt and Sirius lets out another quiet whine, ducking to nose at his temple, sniffing worriedly and licking at his cheek once more.

He doesn't want to hear what Kieren has to say, doesn't want to acknowledge those words and the possible truth in them. It doesn't seem fair is the thing. He feels like he's barely gotten to know Kieren at all yet; after all, it's only been these few months. And already this disease inside him is threatening to take him away.

In a blink, Sirius transforms back into himself, remembering at the last second to spell himself some clothing. He has his arms wrapped around Kieren, lips pressed to the shell of his ear. "I won't let it," he says even though it feels like possibly a promise he can't keep. "Your bloody Muggle science may fail you, but there has to be a spell. I'll talk with Harry again. Magnus, too. Kell. We'll figure something between us, we'll keep you safe, love."