The Magma Orb is an item in Golden Sun: Dark Dawn. While vital to the plot, it is never formally obtained by the party.
The Tuaparang commanders Blados and Chalis manipulate Matthew's party into a battle with the Mountain Roc with an additional threat that the Sanan princess Hou Ju would be boiled alive if the Magma Orb was not retrieved. After defeating the Mountain Roc, they find the Magma Orb within the creature's belly. Having learned previously of the dangers of the Alchemy Dynamo, the Adepts attempt to leave it behind. However, Ryu Kou, Hou Ju's brother, was traveling with the Adepts and took the Magma Orb for himself. Eventually, Ryu Kou would be manipulated into using the Magma Orb to activate the Alchemy Dynamo, causing the Grave Eclipse.