Treasure Digger and Stone Wall Issues

[kjara]

Well, I manage to dig 3 times in most non-hero/map guard battles--start digging once the battle is well in hand(but way before they are down to just 1 troop). Having inquisitors helps (w/ 3x the rage boosting skill) + having points in the +% rage skill in the warrior tree.

Note that once you upgrade it to 3/2 at 13 cost, the -5 rage upgrade becomes available which can bring the cost back down to 8.