When the turn starts, each player may pay 1 Force to put 1 credit counter on a unit.
Each unit with 1 or more credit counters on it gets +1 health.
Each unit with 2 or more credit counters on it gets Fortitude.
Keywords
Fortitude
Fortitude: An isolated, static ability that means, "This unit can prevent unpreventable damage to itself." Units with Fortitude can prevent damage from units with Ferocity and "damage... that can't be prevented" by using Deflect, Evade, Parry, and other damage prevention abilities. Fortitude only allows a unit to prevent unpreventable damage to itself, not to other units. Putting damage counters directly on a unit is not the same thing as doing damage, and also can't be stopped by Fortitude.