Bold Gallantry
Rewritten by the pack's Rules Updates section, and the amended text is what appears here: each time an IMPERIAL KNIGHTS unit from your army Advances, until the end of the turn, ranged weapons equipped by IMPERIAL KNIGHTS models from your army have the [ASSAULT] ability. Read the scope carefully, because it is broader than it first sounds. ONE unit Advancing turns on [ASSAULT] for the WHOLE ARMY for the rest of the turn, not just for the unit that Advanced. That makes the cheapest, most expendable model on the table the switch for everybody else's guns, and it is why this detachment plays as an aggressive one rather than a mobility tax.