Arcanus

Arcanus (エース Ace) is an antagonist in Golden Sun: Dark Dawn. He appears to be aligned with Blados and Chalis as part of Tuaparang. Like his cohorts, his Japanese name Ace is related to playing cards, which may denote that he is considered part of their team or unit. His English name refers to the two complete decks in tarot, including the 22-card trump set of the Major Arcana and the 56-card suited set of the Minor Arcana.

Arcanus later reveals himself indeed to be Alex from previous games using the new alias, His introductory bio states that the Warriors of Vale seem to know his face, but despite that his "true identity and nature are shrouded in mystery." His actions and those of Matthew's company will together have a great impact upon the fate of the world.