Griffon

When in melee units with this special rule count as having caused +D3 wounds when determining who won the combat.

Units with this special rule may move through other units and impassable terrain and they may ignore terrain effects.

Models with this special rule must accumulate X wounds before being removed as a casualty.

If a model with Tough joins a unit without it then you must remove regular models as casualties before starting to accumulate wounds on the model with Tough.

When a unit with multiple Tough models takes wounds you must accumulate them on a single model until it is killed before starting to accumulate them on another.