Props to Tefty from Planet Destiny for the inspiration. The new game mode is Infected v Guardians. There is a 1:3 ratio of Infected to Guardians and the goal is to either survive for a certain time period or get to x amount of points (100 points per kill, no additional points) or for everyone to become infected. This could also tie into how you get Gjallerhorn as during this game mode, the amount of Guardians you out survive would contribute to getting the materials to make it.