The first one that comes to mind is from Leigh Bardugo’s Grisha trilogy and that is The Darkling. While I realize that The Darkling’s power is simply stronger than that other Grisha and that no one really knows how or why the Grisha have their powers, some of the things he can do that other Grisha can’t are just… demonic if you ask me. Not to mention, Alina as a Sun Summoner seems to be his polar opposite and she’s pretty much considered the key to saving Ravka from The Fold. So yeah, I’d say The Darkling fits.
Then we have Crowley from Good Omens who is literally a demon. Probably the universe’s most inept demon, but an actual demon nonetheless.
Another character I equate with demonic, or nearly there, is Voldemort and his merry band of Death-eaters. I mean, seriously, how much more evil can anyone or anything be? He’s pretty much the devil of the wizarding world with the Death-eaters being his demonic minions. Dude need a chill pill… and a nose… just saying.
Ok, so those are the characters I can think of off the top of my head who are demonic. Even know I’m pretty sure I’ve read other books or know of characters that are also demonic in nature, I can’t think of them off the top of my head.
What characters do you know of that are, or are darn near close to being, demonic?