Your artwork is so fantastic! I'm sure it's been said tons of times, but even the little skeleton warrior in the dawn of the dead box is fantastic. It's little details like this that makes a faction feel unique, complete, and fun!
Laying warriors down to signify that they're infected is very easy to follow and a great indicator of their state! Too bad this won't work on the VB lol, but that lil gremlin is always causing problems and def is not an issue I would even worry about.
Corrupted items is a really cool ability, and the wording you've used makes it really clear! It's especially valuable considering the goal of your faction. I feel more mechanics should you with the core rules of root in an intuitive way like this!
I like your balance and scoring mechanism, though I think you've got such a good core storyline and action board here that I feel we can push the way of scoring away from spending cards. Just since spending cards is already an integral part for your faction in birdsong, and I wanna see that crafting ability berry used as well!
Awesome stuff and very creative!