Eying the mark as Kell presses his fingers against pale skin, Sirius feels a strange sense of unease. As impressive as Kell's wall of steaming water had been, Sirius is oddly certain it had only been the very tip of this man's capabilities.

"Normally you can?" he asks, eyebrow arched. "And he can feel you?"

Sirius isn't certain he even knows what it means to bind one's life to another's, can barely comprehend the sort of magic that must be necessary for such a spell. Yet, somehow, he finds himself believing in the possibility.