Models with this special rule can only be taken as part of a unit of Rat Ogres, or a unit of Giant Rats. Models with this special rule (including command group models) must be positioned at the rear of their unit, making up its rear rank(s). Any Rat Ogres or Giant Rats the unit contains must always occupy the front rank(s) of the unit, pushing past any models with this special rule to get there if necessary (such as when the unit turns).

Note that a Master Moulder may issue and accept challenges even if they are not within the fighting rank.