He first appears in Golden Sun when Babi vanishes. He explains to the guards at Babi Palace that Babi has gone missing before, literally vanishing into the depths of Altmiller Cave (thanks to the power of the Cloak Ball). Although concerned, Iodem is powerless to find his ruler. At this time Isaac and his party happen to enter Altmiller cave and, being Adepts, manage to find and rescue the lord. Proving his worth as a reliable fighter by winning that year's Colosso tournament, Isaac is entrusted with the task of finding Lemuria, which holds the mystic spring that flows with the waters of immortality, the key to prolonging Babi's already abnormally long life. Thus, Isaac's party sets out to the south. Iodem accompanies them from this point on, heading through Suhalla Desert and Lalivero until they reach the ultimate entrance to Venus Lighthouse within the ruins below Babi Lighthouse, which prevents non-Adepts from entering, thus forcing Iodem to simply wait by the door for Isaac's return.
He carries with him the Black Orb that is needed to command Babi's ship. If the player travels to Idejima, he will attempt to use this device to raise Menardi's ship, mistakenly believing it to be Babi's, which is in fact securely docked in Lalivero. After the Venus Beacon is lit, he hands the Orb over to Isaac so that he may search the seas for Lemuria on Babi's behalf.
As a senior officer, he has command of Tolbi's military and has many men under his service. For instance, the military troops stationed at checkpoints like Gondowan Passage and Suhalla Gate, as well as with casual forces, such as the Ruffians that Jenna fights in the prologue to Golden Sun: The Lost Age.
Many fans assume when Babi dies at some point in The Lost Age, Iodem takes his place as Tolbi's new ruler.