Be careful of the wings. [Vash wouldn't admit it, even to himself, but that hiss brought him just a hint of satisfaction. Just a tiny bit.] Eventually they won't be so sensitive, but if you injure them you'll get sick because of it.

[There's a pause. Debating with himself, should he warn Knives about what happens if you lose both wings? What if he went and then used that to harm others?]

Also, death isn't exactly permanent here. If you die, the Malnosso will bring you back after some time, but they always take something. You never really know what until you wake up again.

[A compromise. He decides to let Knives process that thought as he debates with himself if he should tell his brother more about the wings.]