He is a ghost born from the regret of men never falling in love. As a ghost he was rude, foul-mouthed, gross, had mucus come out of his nose, farted in public and was generally unpleasant. However due to Stocking's weird taste in men, she fell in love with him instantly.
This actually made Panty protective of her sister as Stocking was willing to forsake Heaven itself to be with Patrick and left the church despite Patrick's very unpleasant personality. Panty disguises herself as Stocking and attempts to kill Patrick, but is stopped by Stocking's arrival. Panty tells Stocking that Patrick doesn't even love her but Patrick says he does and gives Stocking a dung ring and proposes. Stocking accepts but this act purified Patrick's spirit, allowing him a entry to Heaven. The Anarchy sisters then get one Heaven Coin. Stocking then looks up at the sky and sees a new constellation in the shape of dung.
His name is confirmed in the booklet for Panty and Stocking With Garterbelt Blueray/DVD Volume five.
He is one of two ghosts in the series that wasn't evil and didn't cause harm to Daten City, the other being Husband Petter, who made an official citizen of Daten City but was murdered by his wife.