Yeah, it'd be weird if they released a character whose ace was already available, huh. Like imagine if we got the Paradox Brothers after Gate Guardian was released, or Divine Neos before Jaden/Yubel. That'd be crazy, right?
Seriously, though, they could just not give him an ace, or give him Volcanic Queen as one, or have Doomfire still be his ace like the 5D's characters.
Is Volcanic Queen in the game yet? It might end up being her. If not, it could still end being Volcanic Doomfire (similar to Paradox Brothers' ace Gate Guardian, being available already.
I wonder what will be the rest of his level up cards and drops if he becomes unlockable, though.
Queen and Slicer will be in for sure, but what generic cards will be used for the rest? They probably can't bring Scattershot because it's an easy field nuke.