||Nasty parasitic creatures, leeches can be encountered in both wet, tropical vegetation and in boggy waters. They attach themselves in countless numbers to any living crea- ture possessing blood which passes through their territory, stealthily wriggling under clothes with maddening ease. With naturally anaesthetic saliva they can feed without the host even noticing the infestation, although falling into a pit or pool full of the little horrors might be obvious. The consequence of leech shoals is somewhat different than other types, taking several hours to take effect. The swarm only rolls for the number of injuries once, armour having no effect. For each two points of injury the victim suffers a persistent level of Fatigue from blood loss and secondary infection
Unless there is some good reason, the collective affects every Hit Location of a target which fails to Evade, Fly or Swim clear (as applicable).
Melee weapons are useless against a flock, horde, pack or shoal since each blow can only kill a tiny proportion of the entire group. Each individual creature is so minor they possess no Characteristics, but the collective itself is given a number of Hit Points to disperse it, assuming the characters have some sort of area effect attack capable of damaging a volume rather than a single target.
Unlike insect swarms, these groups can inflict different types of injury rather than just poisonous stings. The size of the group determines the number of ‘injuries’ it delivers at the start of every round. These are automatic and cannot be avoided if it has engulfed the victim.