Trait: Strike from the Darkness

The Chapter is superbly trained in stealth or in possession of some ability that allows its’ members to hide even while in the open. For a cost of +6 points per model, any enemy unit that wishes to shoot at any unit in the Legion army must test as if the Night Fighting rules were in effect. If this test is taken by a vehicle with a spotlight, and it is passed, the rest of the enemy army may choose to fire at the targeted Legion Unit with out needing to test on the Night Fighting Rules.

My idea for this was something along the line of Ghost in the Shell's Therm-optic Camo. It makes them invisible but not imperceptible.