Flesh opens. Blood flows, and it's more than just a bite he's going for but ripping. There's a sense this is not the first time, that he's done this before—fought tooth and claw for every inch he's gained. A certain grace might've existed when he held a sword, but when his jaws clamp down they do so with an instinctive viciousness. Too much filling his head, probably, driving him forward without restraint.

Only an arm through his chest gets him to release. He almost doesn't feel it so much as it simply happens, and then there's a different taste of blood filling his mouth. A minute or so where he's just choking, nails digging into Lucifer's arm. If they were in the physical world, he might've collapsed. He starts to, even, going limp. Then he flickers, vanishes—and lands with an undignified thump outside of it, nearly crushing Jaskier's beloved pet gryphon. He curses.

Maybe the lack of a dead body laying there is a disappointment. But it does leave Lucifer with plenty of time to explore the rest of Kaer Morhen.