It's Always Sunny In Philadelphia: 10 Best Characters Who Appeared After Season One

There can be no other choice.

According to Rob McElhenney, the continuation of the show after series one hinged on them getting a known star to join the cast. Danny DeVito did and not only did he nail the role, he effectively revived his career.

Frank Reynolds is a monster of a human being. His considerable wealth allows the gang to do whatever the hell they want, but it is not a secret that his wealth wasn't built legally. Along with his shady business practices, Frank is a drug using, hard drinking sex pest who frequently 'bangs' anything with a pulse.

His only real relationship is with Charlie, who is most likely his biological son. Beyond that, Frank treats the gang with contempt, only showing an ounce of compassion in the wonderful episode where Mac comes out to his father. It comes thirteen seasons into the show but it is completely worth the weight.

Frank is brought to life by DeVito who dives head first into the role, seemingly having the time of his life in playing such a horrendous human being. Some of the things they get the legendary actor to do is side splittingly hilarious and the coup de grâce is his escape from a leather sofa, where he was hiding at his own fake funeral. Seriously, just YouTube 'Frank in the couch' and bask in ALL the glory of the legendary Frank Reynolds.