To improve the granularity and realism of combat, the optional “monster size” rule may be used. This rule increases or decreases an attacker’s odds of striking his or her target based on the size of the monster.
Extra small (XS) – -1 to melee and ranged attacks against extra small monsters (e.g. pixies, fairies, imps, etc.).
Small (S) – -1 to ranged attacks against small monsters (e.g. giant rats, blackscale leeches, cave nymphs, etc.).
Medium (M) – no effect (e.g. werewolves, humans, hobgoblins, etc.).
Large (L) – +1 to ranged attacks against large monsters (ogres, giants, basilisks, etc.).
Extra large (XL) – +1 to melee and ranged attacks against extra large monsters (dragons, bathemoths, tyrannosaurs, etc.).