Invisibility works the same regardless of whether it is an invisible character or an invisible monster. Monsters can't focus on invisible characters, move through them (unless flying or jumping), or target them with any attacks or other targeted abilities (an ability like "CURSE, target all enemies within range," for instance, wouldn't affect the invisible character even if he/she were in range). Monsters essentially treat invisible characters like obstacles, but may occasionally affect them with non-target effects (such as splash damage). Once again, however, an invisible character will never be focused on by a monster.

Invisibility can create an edge-case where a monster is unable to find a focus, either because all of its enemies are invisible, or an invisible character is standing in a door or some other one-hex passageway to prevent a monster from finding any viable path to get within range of an enemy. Blocking a passageway like this doesn't always result in not finding focus. Flying or jumping enemies can ignore the obstacle (invisible character), and ranged enemies may still be able to shoot over it, depending on the value of their range and the positions of the other characters.