The thick-eyebrowed, cartoon nun in the screenshot above is named Sister Mary and is sometimes referred to as The Special Sister. She's a major antagonist from an old, obscure Adult Swim cartoon called Lucy the Daughter of the Devil (I'll just call it LTDOTD). Created by Loren Bouchard of Bob's Burgers fame, LTDOTD was the first cartoon on the block to be animated using computer-generated imagery, as well as the first to have a female protagonist in the lead. It was rather short-lived, running from 2005 to 2007, with a total of 11 episodes, including the pilot episode.
LTDOTD follows Lucy, a 21-year-old young woman who is indeed the daughter of The Devil, both of whom are hardly evil at all, and lives in San Francisco. She was ordered by her father to fulfill her destiny as the Antichrist regardless if she likes it or not, and along the way, meets a disk jockey named Jesus (pronounced "hay-soos"), who is the Second Coming of Jesus Christ himself and they date after she saves him from a fire The Devil created in order to kill him. On the side, The Devil attempts to take over the world through a variety of "evil" schemes with the help of his advocate Becky, who acts more like an assistant, and in the meantime, there's a clergy known as the Special Clergy consisting of two nonchalant priests named Father Giuseppe and Father Benetti, and a grouchy nun named Sister Mary (the nun in the screenshot above) from the Vatican on a mission to kill Lucy.
Sister Mary is shown to be the deadliest of the three clergy members and is the most dedicated to destroying Lucy. She gets angry very easily and, despite being a nun, she is not above killing innocent bystanders who provoke her even slightly, and has inevitably done more evil deeds than Lucy, even though Lucy is the antichrist. Sister Mary is easily my favorite character in the show, not to mention the fact that Eugene Mirman (who would later go on to voice Gene Belcher on Bob's Burgers) did a phenomenal and hilarious job voicing her.
