The Ancient Guardian is a cosmic entity in Spore Hero, originally being a statue of a bipedal creature with only four limbs that support the basic hands and feet. Your character must finish his stone sculpture with parts you collected from each world, starting with the feet from Mushroom Valley, following the mouth from Moonlit Stoneway, then the sensors from Moonlit Caverns and the hands from Mushroom Grove (path is interchangeable between the two), finally the weapon from the Ancient Grounds, and details from anywhere in between.
The guardian then comes to life and grants you access to Creature Beach. Afterward, you must give him the Claw of Courage to get an organic obstacle out of his way and the Feather of Charm so he can help you gain access to the Ancient Brain. After you give him the Ancient Brain, he does a position similar to that of a creature being zapped by lightning, then gains the ability to talk, claiming that he is not the guardian from the legend and that your character is, stating that he/she is the one that came from the sky. He then creates the Spor-O-Mega and will not let you fight Zarkhator unless you equip it on your character.
After you defeat Zarkhator, he can be seen walking around in the Ancient Grounds, still editable. When you talk to him, he says that the legend was not entirely false as it stated that he and your character are actually one. He also asks your character about what happened to his/her and Zarkhator's homeworld. He then says that he will be a gardener in the Ancient Grounds since his duty in the legend is done.
The Guardian Idol has some parts that are basically the same as ordinary ones but with different names. For example, the Cassoworry wings are labelled as the Eaglewing wings. The parts also have slight differences from regular parts, being that all eyes are pure blue, golden facial features appear on the mouths, the keratin of the parts are replaced with crystals, and some of the permanent colors of certain parts are replaced with gold. Also, when editing the Guardian Idol, his limbs cannot be edited or removed in any way besides changing the distance of the body from the ground, scaling the hands and/or feet, and interchanging where the hands and feet are placed. The structure of the torso is also unchangeable .Also, the Guardian Idol is the only editable creature in the game without the ability to change the color of the body.