When each battle phase starts, if you retreated 1 or more units last turn, you may choose one of your Space units. If you do, the chosen unit gets Fortitude (This unit can prevent unpreventable damage to itself.) and Parry 2 until end of turn.
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.
Parry
Parry X: A cumulative ability triggered during the damage prevention POP that means, "If the attacking unit rolled at least one natural '1' against this unit, prevent X damage to this unit." Only one natural "1" is counted from the attack roll after re-rolls. Parry doesn't prevent damage from a parrying unit unless it attacks itself. Parry can't affect unpreventable damage. If a unit gets the Parry ability after you roll attack dice, it's too late to affect the damage. Accuracy can't decrease the die roll to a natural "1". However, you or your opponent may use an effect to re-roll dice to affect the number of natural ones. (You only count the 1, if any, from the roll used for the attack.) Parry applies only to dice rolled for an attack, not to dice rolls for abilities like Retaliate.