Strider (Forest) Models with Strider will normally have a subset of Strider that is mentioned in the brackets. The rule only applies in terrain of the specified type. Models with Strider treat that piece of terrain as open ground for the purposes of Movement, meaning they ignore any M penalties or Dangerous Terrain tests otherwise caused by it. Note that they still follow the rules for that terrain type in terms of combat.
Primal Fury At the beginning of each round of close combat, each engaged unit with Primal Fury must take a LD test. If the test is passed, that unit gains Hatred until the end of the close combat phase. In addition, if the successful roll was a double, they also gain Frenzy until the end of the close combat phase.
