According to the new rules Resources(ATA's,Feats,Gauntlet) assigned to your characters can't be used by an opponent if they become unfriendly to your force.

But it's not the opponent's ATA I was asking about. I'm saying if you have the ATA on your force, and MC a guy on the opponent's force who has the keyword required for the ATA...would he get the benefit of your ATA while you controlled him?

No, you can't use ATAs on MCed characters.

I'd think that you could pay for it on Blake but would only be able to use it if you managed to turn into Thor. And then you'd be able to legally use it?

If you're using my incredibly and completely unofficial made-up-by-me rule, then yes.

Sig material, there.

Based off the ATA rules, at my venue I will be ruling that you do not have to prepay for the ATA.

This kinda came up with the SHIELD ATA on Mo-Hawk and splitting them into Hawkeye and Mockingbird at a home game.

Would I pay twice for the ATA on the ? No. Once is enough. So when they split who gets it?

According to the rules, building a team and using the ATA are two different functions. One must be assigned to all figures that qualify. In game, everyone meeting the prereq must have the ATA assigned.

That's how I'm doing it.