A model with this special rule that begins the movement phase within 1" of a friendly unit whose troop type is infantry, that is not fleeing and that contains ten or more models, may replace its Movement characteristic with the Base Movement Characteristic of the unit. If a model does so, it may only declare charges against units also charged by the friendly unit within 1".

If a model with this special rule is also a character's mount it may join a unit of Infantry. If it does so, it must always be placed in the centre of the front rank.

Furthermore, if this model is a Heavy Chariot, whilst it is part of the unit, the model no longer has the Lumbering rule, and may ignore it for the purposes of joining the unit. Only one model with this special rule can join each unit.

if the model with this rule is unable to fit neatly into the unit, count its front facing as if it were on the correct base size for all purposes for as long as it remains in the unit. lE: a Screaming Bell (60mm x 100mm) counts as having a front facing of 75mm when it joins a unit of Clan Rats or Stormvermin (25mm x 25mm). To achieve this, you may use a spacer, or simply leave room to either side of its base on the movement tray so that rear ranks can close around it correctly.