Luckily for Rin, Stocke's already shaking off intangible edges, solidifying. He'll need to be in a tangible form to "bleed."

There's a few uncertainties here yet - Stocke still doesn't have a good reason to trust Rin, besides words, and there's no saying that Mana's magic will go the way she wants it to. But... though the shade pauses, it's not a long one before he nods sharply. He'd already decided it was worth those risks heading over here.

"How much do you need?" Stocke reaches for one of the glass vials even as he asks, flipping it upside down in his hand. He digs one claw into his opposite arm, making a short, shallow cut, and holds the container over it to catch the dark smoke that spills out.