Don't know for sure how to do it yet but I can say it's not from 100% areas...I've done this to a few and haven't received anything but a couple A rank cards. It might have something to do with playing online matches...I've only played 2 of those...lost both too...yay me...lol You still get H&H points when you lose though so...guess I'll get beat some more and see what happens.
The one thing I will say is terrible about this game is that even though the person I'm playing against and I BOTH have excellent connections but the game still jumps around with lag to the point it's almost unplayable...never happens with any other game I play online...weak...
It might have to do with getting 100% in all regions for a faction. I'm actually close to this one for one side, so I'll try finishing it tonight. It might also be the weekly prize for the online version, perhaps? Although truth be told, I don't have a lot of motivation to play this against randoms. Without being able to play who you want to, this will quickly devolve to a few choice cards for the cheapest combos possible. ^^;
GT: busyyuusuke Currently playing: UMvC3, SSFIVAE, L4D2, GoW3, Arkham City
There's no confirmation that they are unlockable offline. For now, it looks like they may only be given as rewards at the end of each week for the winning team (Though that seems unlikely to remain the only way to unlock them, as it would require almost a full year of being on the winning team to unlock everyone....)