It's Always Sunny in Philadelphia/Frank Reynolds
Frank Reynolds is the father of Dennis and Dee. He is also part owner of the bar with Dennis, Mac, and Charlie. Recently divorced, Frank is preoccupied with attempting to relive parts of his life that he has missed because of marriage.
Frank shows up at Paddy's to see Dennis and Dee and tell them that he has gotten a divorce from their "whore mother". He says that he wants to spend more time with them, but in Charlie Gets Crippled he winds up hanging out with Charlie and using his status in a wheelchair to try and pick up women. Even though they don't want him to stay, the gang eventually accepts in Frank after he becomes part owner by buying the building next door in The Gang Goes Jihad.