The Guardians of Eternal Youth are five big chubby babies with deep voices that granted Skips eternal youth. They are only shown during Free Cake and Fists of Justice (also during Brain Eraser and individually during Skips Strikes). They demand that Skips needs to perform a ritual on his birthday to retain eternal youth, and they try to take it away from him when Rigby interrupts Skips during the ritual. They apparently love cake (especially chocolate), since they restored Skips' eternal youth in exchange for cake (which they rubbed on themselves, much to Rigby's dismay). The leader appeared in Skips Strikes as a member of the Magical Elements. In Fists of Justice, they call Skips to fight Klordbane the Destroyer, their evil brother. However, because Skips broke his hands, Mordecai and Rigby have to maneuver the fists; they are able to defeat Klordbane. The Guardians say they will give anything to Mordecai and Rigby because of the victory, and Mordecai and Rigby spent it on moving the harpsichord.
The Guardians of Eternal Youth's Belongings
The Guardians of Eternal Youth's Realm (The area they live in.)
- Their clothes are much like the Time Lords in the show Doctor Who.
- They appear four times in the series; first in Free Cake, again in Brain Eraser in as one of the pictures from Mordecai's eyes, Skips Strikes and finally in Fists of Justice.
When the leader appears in the episode Skips Strikes, "GB" is shown on the scoreboard for bowling, which would be the leader's initials due to the other names being up there. "GB" may mean "Giant Baby".
- In the episode "Fists of Justice", one of them dies by getting stabbed in the chest by Klordbane the Destroyer. It is unknown if that Guardian will return.
Since the death of Archibald, there are only four Guardians left. It is also known that the Guardian that died is named Archibald as Klorgbane said, "Hello, Archibald".