Honour of the Household is the heraldry a lance rallies on — the banner of a household that has not broken in ten thousand years, borne by the Knight Preceptor or the Knight Seneschal.
While a friendly fighter is within 12" of the banner-bearer, it stands under the household's oath. Such fighters — the war-engines of the lance and their Sacristan crew alike — automatically pass Nerve tests and are immune to the Terror that war-engines and monsters cause. Once per battle, a fighter within the aura may re-roll a single failed Ion Shield save, the banner turning aside a blow that should have told.
The aura reaches only 12", and it moves with the bearer. A foe that isolates an engine beyond the banner's reach, or cuts the bearer down, strips the lance of the discipline that holds it together — and a household that loses its standard fights the rest of the battle alone.