Silmarillion concept that has me gnawing on the bars of my enclosure today: all of Elrond's parents are terrifying eldritch beings actually.
Maedhros, with white fire pouring from his eyes, taken from the jaws of death anything but unchanged. Some whisper that he's not elvish anymore, not since his captivity. They can never quite agree on what that makes him, exactly.
Maglor, with a voice no elf ever should've had, beautiful and terrible and powerful enough to shake the mountains. Sailors along Middle-Earth's west coast whisper of a sea wraith, some horrible siren that roams the beaches on the darkest nights.
Earendil, a man made an elf, a star, a maia if some are to be believed. Slayer of dragons, guardian of the void. Someone who's spent so along around the Silmaril and the Ainur that some of that power lives within him now.
Elwing, a skin-changer with a voice and a laugh that sound like they were taken from a bird's throat. A witch who lives in a lighthouse, where the animals flock and the plants grow strangely. None of the Amanyar would admit to being scared of her, but few will venture in sight of her odd little realm.
And then there's Elrond, ring-bearer, Lord of Rivendell, kind as a summer.
Well, let's just say it probably helps that no one is expecting him to be normal. Or elvish. Or entirely comprehensible.