Been playing this quite a lot recently with some good results, some of the new Arroyo really filled the holes that spirits had. I've been fiddling with this a lot since the exp landed and i think i've finally got it in a good place though i would like to see some comparisons with what others are running as it definitely isn't perfect. Early game tends to be quite hard as even though a few of the champs are pretty good alone the real strength doesn't come until later so strong early game opponents like UD and SL can be problematic. The good thing is that i find if i can hold out for the initial rush until i get my important units down then the bg hits 'critical mass' in no time. Annoyingly Riftwalkers are perfect for shutting down rushes but with Vuln:Fire they often aren't an option against UD/SL. The spam of little spirits from the Riftlords is pretty much the first step, this gives Shadestrikers, Magistrates and Whisperghasts a nice damage bonus which hits very fast if you are able to get five or so real spirits down too. After this looking for a strong powerturn with a Magistrate in range of a couple of kills will often secure the game just like that. The spirits just keep rolling out and as long as the Magistrates and Riftlords are safe the damage just keeps going up and up.
