I have been testing different strategies for life and the cheapest one I found that is really effective against warlords is to simply never attack. Basically I took all the attacks out of my deck replaced them with heals and replaced all my tc with tower and spirit shields with a about 3 reshuffles. If they didn't run out of cards they fled. Yes this is a ultra cheap strategy but a good one if you want to get to a high rank in pvp. But if your aiming to make friends this is not the strategy for you cause not very many people like being beaten by a guy who never attacked.
