Lucifer

Lucifer has light-blond hair, snow-white skin, and red cheeks, similar to Charlie's. His eyes have yellow irises and red, thin pupils, giving Lucifer a snake-like appearance. He wears purple eyeshadow on his eyes. Lucifer has, at least in the illustrations, a pointed grin, with a mouth full of sharp teeth.
His clothes are in a general light pink style with red linings, black and purple elements and apple symbols, which are also present everywhere in the hotel, from the stained glass windows at the entrance to the furniture, giving reason to claim that the hotel is a family estate. He wears:

a tall top hat with a red band wrapped around it with a pale yellow snake and decorated with a red apple with a light leaf on the stalk,
the same style as the hat, a long, sideless coat with a red trim and 4 long black cord loops with gold buttons, as well as a high collar, pulled in by a simple black bow tie,
a red vest with white vertical lines,
black arms up to the elbows,
white breeches,
black knee-length boots (shown in one of the paintings, which depicts the entire Morningstar family with several unknown demons) and carries a thin black cane with a knob similar to the decoration on his hat - a red apple with a light leaf on the stem.