Valkyrie: Expanding 2

Look at the number of card's here.. 

Did you notice that you have 2 cards locked? Starters would have 3 cards per attack unit including the defense unit. If you do have locked card slot then you need to build an Arena for your attack unit and a Fort for your defense to unlock those slots per level.

That will help you do more damage on your campaign and archwitch hunting.

By now with all of those campaigning and having a maximum card slot you might be having problem with two things,  your Valkyrie card's recovery and or unit cost. Since you don't have yet high cards that can land one hit to all of your card's enemy most of the time your unit will end up annhilated which takes up most of your resources. Or you want to put in all those strong cards but it just can't fit in with the current unit cost that you have. You should know by now that you can only put in those cards that can fit in on your unit cost which is troublesome if you have higher cards. If you don't know what I'm saying i suggest to read the Cards post.Valkyrie: Card1

You need to build these to solve your problem.

The Parliament building will help you reduce the recruitment cost at 10% on lvl 10 max. You can build a maximum of 3 which gives you 30% less cost.
While those Barracks helps you add unit cost. It'll give you +46 unit cost on lvl 10 max. A maximum of 3 Barracks can be built. That will add 138 on your unit cost.