A list of terms that i keep using explained for the uninitiated.
Advantage and Disadvantage
If a character has an opposing character in more than one adjacent square they are at a disadvantage as their focus is divided by 2 or more enemies. As such their save value is cut in half when defending. When rolling their accuracy roll they must roll twice and take the lower of the 2 rolls.
Conversely, if 2 of the same force are in adjacent squares to one enemy, they are at advantage. They roll twice for accuracy and take the higher of the 2.
In the rare instance when a player is at both advantage and disadvantage, it will have null effect and play as normal.