Lucifer: Dearie me, these are atrocious. What self-respecting artist would actually display these?
Dan Espinoza: Dave Maddox isn't a real artist.
Lucifer: To say the least.
Dan: All of this is just a front. You see, criminals like Maddox, they use art sales to cover up money transfers. They can demand any price for a piece of art, and in return provide whatever it is their clients really want.
Lucifer: Can he provide an eye bath? I'll need one after this.
Everything's Coming Up Lucifer - S2-E1
Lucifer Morningstar: Hello. My name is Lucifer Morningstar, and I love drugs! Love them. Mmm. Yummy, yummy, yummy. Can't get enough. And I've got lots of money. [Pulls out cash and sniffs it.] Mmmm! That I love spending on drugs.
Answer: It's Lucifer's blood from when his wings got hit by the bullets. As Lucifer spreads his wings, they're white, and before he wraps them around Chloe, you see a bullet hit his wing above his right shoulder, and the spot turns red. After that, he continues to get shot in the wings before fleeing.
Bishop73
Agreed. His wings take damage and "bleed" similar to how he bleeds when Decker is around.
Ssiscool ★
If they were normal bird's wings, the lower part where there are just feathers should neither bleed like that nor be able to stop bullets, but they are angel's wings, so they behave differently.