Siege breakers are Ogres who specialise in breaking down castle gates -- they carry hugely destructive hammers and protect their advance using giant tower shields. An Ogre can only afford such tools if they are veterans of a mercenary company, as each set of armour, weapons, and shield uses enough metal to armour a regiment of human knights. Warriors of such skill and wealth are rare, which is a relief to most human lords who hire or battle the ogres.