A character in Bram Stoker's novel "Dracula." Renfield is an incarcerated lunatic who serves Count Dracula. He is zoophagus, which means he likes to consume other lives. In Renfield's case, he likes to eat flies, spiders, and sometimes birds.

Personally, I always imagined him as a guy whose exposure to horror has opened his mind to the true nature of the world. He's not insane -- he's actually the only completely sane person on the planet. That's why Drac keeps Renfield around -- he doesn't really need a servant, but he's not going to refuse the services of an oracle...

Renfield has been played by Dwight Frye in the original "Dracula," by Tom Waits -- let me repeat: Tom Mothafuckin' Waits! -- in "Bram Stoker's Dracula," and by Nicholas Hoult in the 2023 horror-comedy movie "Renfield."