Haven vs. Fortress (how to play against dwarves?!)

I recently started playing on ubi.com with friends. We like to play for longer periods to fully enjoy the game, but I've encountered a problem: I can't find a strategy to play against the Dwarves. It seems like after level 25, it's impossible to defeat them with their endless resurrection runes, etc. I don't know what to do in this situation. I'm playing as Haven, with the hero Axel, version 3.1. Does anyone have any ideas?