The Branch & Claw Expansion for Spirit Island features:

Two new Spirits! (Sharp Fangs Behind the Leaves and Keeper of the Forbidden Wilds)
A new Adversary! (France)
A new step added to the Invader Phase of the game: Events! The Event Deck has events that happen each turn, adding further variation to the game play.
New Tokens that can be added to the board! Wilds, Disease and Strife Tokens prevent the Invaders from Exploring, Building and Ravaging, respectively, and Beast tokens represent the wild beasts of the land that will help you out when you least expect it.
New Power cards: 31 Minor and 21 Major, many of which make use of the new Tokens!
15 new Fear cards!
New Blight cards and new Scenarios!