I played the game yesterday and it came to some questions.

1. Can I Upgrade green Ally Infantery to Knights?

2. If another Player steels my Ally Card, do I loose my troops?

Thanks for answer, and sorry for my bad English.

1. No you can never upgrade allied armies, nor remuster them once they've been killed. The only way to gain new allied forces is for the army ally card to switch from one player to another (through the relevant Plot ally card).

2. Yes. The other player then gains the new troops as indicated on the card (even if part or all of your ally army has been killed).

By the way, you keep the ally army card, even if all your allied troops have been killed.

Also note this case:

You have two Ally Army cards, Sellsword Army (footman) and Tyrell Army (footman and a knight). During the game you lose an ally footman. In the next round someone steals Tyrell army card. You are forced to remove the knight, but not the footman, since you are allowed to have one ally footman due to the Sellsword Army card.

Also, the person losing the allied troops chooses which troops will be removed if he has multiple ally troops.