The Master Spy is the most frequently seen of all the Master Templars, having appeared at several different points in the story. He's disguised himself as an innkeeper twice, as a shopkeeper once, as an underling to a guild leader, as the person introduced to Trace during his first trip to the Templar academy, and as the carriage driver the day Trace's wife was killed. He has demonstrated the ability to disguise himself as a Basitin, as well as helping Trace and his friends on their journey many times, from giving Trace the SubtleSeed Crystal to killing the Arms General . He has some connection with Euchre, and was at one point the Master Spy in Trace's inner circle. He introduces himself as Edmund Sirus, and is called such by his friends in the Templar school. It should also be noted that he always has bandages wrapped around his right arm, regardless of the disguise he is using.
It is assumed that he favors helping Trace out as much as possible, regardless of Trace's choices. He demonstrated this by helping him form a bond with Flora through the Subtleseed crystal, helping Euchre protect Trace against Ephemural, and not trying to force Trace to turn back into his old self. This behavior suggests either a kind personality or a close friendship with Trace beyond the role as Master Spy.