Klorgbane the Destroyer was first seen in the episode "Fists of Justice." He was the main antagonist and he is related to the Guardians of Eternal Youth, as their "evil brother." He has to fight Skips every 157 years. His main goal is to defeat Skips, and reign over the Realm as part of the council. He fought Skips for a while, and was ultimately beating him, until he lost to Mordecai and Rigby shortly afterwards.
He looks similar to the The Guardians of Eternal Youth, except his clothes are black (opposed to theirs being gold), and his body is more muscular in appearance. He wears a black helmet or hat, a black cape, a black diaper, black socks, and two sliver/black bracelets. He also has a red glow around him and carries a red rattle with spikes on it.
- Like The Hammer, he is one of the most powerful characters and/or enemies in the series. The Fists of Justice is the only weapon that can defeat him.
- He killed one of the Guardians of Eternal Youth, maybe more, but this is unknown.
- In "Skips Story", it was revealed that Klorgbane caused the death for Mona, the only woman Skips ever loved when she pushed Skips out of the way from Klorgbane's attack and was crushed to death when the attack caused part of the ceiling to fall on her. The reason Skips chose to be immortal was to avenge her death when he would return.