Azrael suffers from a severe fear of the dark and is most commonly seen carrying a lantern, candles or other sources of light.
I also figured that he probably has some kind of medical reason for his rail thin appearance, a congenital digestive system abnormality, an internal parasite or hyperthyroidism, for example. He eats relatively normally, he's just unable to gain weight.
Staedtler pigment liner, Gimp.
Artwork, character ©CanisAlbus