Agility represents a character's mobile ability. It encompasses balance, dexterity, flexibility, and most importantly, proprioception - an awareness of one's own body. Someone who has high agility is precisely aware of what his body is capable of and what it is doing at any given moment. The range for agility is from 0 to 7.
A character's agility may give him a bonus to duck. Higher agility allows someone to move in such a way as to make targeting him difficult.
There are two types of agility rolls which may be required of a character. The first is to roll one or more dice and get a value equal to or under your agility. The second is to roll one or more dice which is added to your agility with the goal of reaching a certain total. The number of dice required and the total the character has to reach are totally up to the referee.
The most common agility roll is when a character is hit. Usually, a hit from a weapon with force equal to ten times the characters mass will require an agility roll. If the character is hit in the legs (placement 5) then the force required is greater than or equal to the targets mass to warrant an agility roll. The agility roll is 1D6 and the objective is to roll equal to or under your agility. Failure means you are knocked down and have to get up the following turn or be prone.
Agility rolls may also be required at the discretion of the referee. Jumping across chasms, climbing loose rock, or walking across a thin ledge may all require agility rolls. Failing an agility roll in these circumstances can have dire consequences.