K'nuckles' Dad is obviously K'nuckles' dad. K'nuckles usually tells stories about him to Flapjack, when in a bad situation. K'nuckles' Dad finally appeared in person in the series finale of the Flapjack Dub. He is the leader of a group called Nomens, a group who helps stranded visitors on Pangea. His real name is unknown, so he is just called K'nuckles' dad. He is a one-time character in the show (despite him appearing in flashbacks).
K'nuckles' Dad first appeared in The Flapjack Dub Christmas Special in a flashback, when K'nuckles told Flapjack about why he doesn't like Christmas. K'nuckles' Dad told him that Santa Claus was a murderer & he shouldn't trust him at all. Because of this, K'nuckles goes out to destroy anything that ever involved Christmas & then soon got sacked by the Hitler Mermaids.
K'nuckles' Dad appears in person in the series finale The Flapjack Dub Movie. First in a flashback, where he told K'nuckles how to actually look like a child which made no sense at all. Then later when Flapjack & K'nuckles were stranded in the desert on Pangea, K'nuckles' Dad & his group of Nomens came to help them. Flapjack told K'nuckles that the leader was his dad. K'nuckles's Dad didn't remember him until he realized his name. With joy of K'nuckles's return, K'nuckles' Dad offers his son & Flapjack anything they want. Flapjack tells him to rule the world & the location of Candied Island & K'nuckles' Dad offers it to the duo. He & the Nomens stayed with K'nuckles & Flapjack on their way back to the beach, but Ganon & 2 giants block their way. K'nuckles' Dad tells them that are trying to crush Pangea. K'nuckles says that he can't fight them due to how big they are. After Ganon recognizes his eye-lens, he becomes ruler of Pangea again & K'nuckles' Dad says that he is stupid. With his son leaving, K'nuckles' Dad says goodbye to him for the final time & tells one of the Nomens to go get a soda, but also knows that K'nuckles took his umbrella.