Hellish Creatures

I came up with some imp/demon characters for my world and story lately. I've been sketching a lot but never coloured anything, soooo here we go! Eli and Lana (which are BTW just shortened versions of their long and weird names) live together in an abandoned basement. Lana enjoys luring helpless humans to their doom while Eli just shakes his head, minding his own business.
<sub>They are NOT a couple.

Bonus points if someone recognises the book lol</sub>

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nightmare shifting - the ability to alter your body (or perception of it) to appear much scarier than it really is. A collective term for a form of shapeshifting, which includes abilities such as nemesis form, matter state shift, and others. Wildly used by demons and other creatures of the dark.