Question: if in a mission there are no open groups and you have the Nemesis class deck that allows you to put a villain in your open groups, can you use that villain in the mission?

Yes. The "add one villain to your hand of open groups" happens no matter how many open groups the mission normally has. And any groups in your open groups can be deployed following normal rules, regardless of how they got there.

There are some other class cards and agenda cards that add cards to your hand of open groups, and they work the same way.

Just to confirm: Yes, it is possible to add deployment cards to a hand of 0 cards.

Specific to the Nemeses class deck: in the early missions you want to have the villain in hand for Inspirational more than spend all your threat to deploy the villain to be defeated by the rebels (villains cannot be redeployed in the same mission). The same applies to the late campaign as well when the rebels can take down the villain in a few attacks.

13 hours ago, a1bert said:

in the early missions you want to have the villain in hand for Inspirational more than spend all your threat to deploy the villain to be defeated by the rebels (villains cannot be redeployed in the same mission). The same applies to the late campaign as well when the rebels can take down the villain in a few attacks.

True - but with the discounts from the base card (and potentially Indomitable), the Villain may take more effort to defeat than another group of the same threat cost. And early on, a villain like Greedo can be a serious threat to the Rebels at low cost to the Imperial player.

Thank you guys!