Deuce’s Unique Magic

In-game explanations and instances of Deuce’s UM have been compiled here ▶︎

Deuce discovers his unique magic by accident when defending Epel from a group of men that were grabbing at him on the beach. He does not realize what it was then, or even after he uses it intentionally for the first time at the end of Book 5 to take out Vil. 

He seems to understand what he did—“that spell stores up all the damage from someone, then hits back with it all at once”—but he did not realize it was his unique magic and cannot remember what he called it.

※ Note: there is a common misconception non EN that Deuce’s unique magic “doubles” the strength of the magic that is hammered into him when he strikes back, possibly based on the localization of his UM (EN: “Double Down”), but this is not true.

Deuce himself explains that the spell “lets (him) store up magic that’s been used against (him) and send it back:” there is no “doubling” involved. While the localization of Deuce’s UM comes from Blackjack, the original name of Deuce’s unique magic is a poker term: “Bet the Limit.”