[So... they're a physical manifestation of his inner conflict. Though Ferran doesn't get that the creatures themselves might be a problem, if they're unpleasant for Vanitas to create, then... yeah, obviously it would be something he'd want to stop.

Ferran looks down at the black marks on his own wrists, pondering for a few moments, and he realizes the idea of them being something to solve hadn't even occurred to him before. That's pretty sad, isn't it? That he'd just accept the pain that came along with them.]

So... what, because you were made of darkness to begin with, the light you've made on your own since then doesn't count?