Discussion about Sylvan (Wood Elves).

It is impossible to know for sure with this ability whether neutral creatures will join or flee. Only the "they will fight" option clearly answers the question. It is best to attack when you have a decent amount of gold, as creatures can join for free or for gold, so if you don't have gold, you have to hope for the altruism of the neutrals (and they are capricious). IMHO, the main advantages of this ability are increased vision and troop camouflage.