Harold Slikk is AGK's Dad on any AGK series. In Adrenaline21 version, Harold's voice can be heard when you watch the 1st episode of Adrenaline21's AGK Series (The AGK Parody Show) and his full appearance shown in 6th episode of Adrenaline21's AGK Series (The AGK Parody Show).
Harold Slikk was born in Germany, 8 January 1965. At his childhood, he was usually heard any metal and rock musics on his radio also he asked to his parents if the poster that contains any metal and rock band that sticks on walls of buildings that around from his city. In the concert, he asked again to his parents that he wanted to be a guitarist on his own band but his dad told him that he wasn't know about playing guitar. Later, He surpassed his skills when he shown to his dad in his teenage age. Several years later, Harold married with the girl named Gladys that he didn't know about her that she was on concert since his childhood. At 1990s-2000s, Harold and Gladys had 3 sons named Leonidas (1995), Leopold (same as Leonidas), and Leonard (2003).
Now, Harold still a guitarist from 2000s unnamed bands he had after the birth of Leonidas, Leopold and Leonard also he has violent attitude to them if they do their annoying activities and ignoring his commands.
References to The Grim Adventures of Billy and Mandy
His name was taken from Billy's Dad on The Grim Adventures of Billy and Mandy.