Islebound: Emerald Edition is a special edition of the game with some altered components and rules. It's best to think of it as a variant of the game, rather than a 2nd edition. This edition removes the book resource from the original game and replaces it with emeralds. Emeralds have different uses than books. You collect them when visiting a player-owned town and when you taking over a town. Emeralds must be used to buy building cards, and they can also be used to perform special abilities, such as keeping pirates and serpents after combat!
The backbone for any hunter cadre, strike teams and breacher teams are the predominate military wing of T'au Empire. Their weapons are the equal to the elite weaponry of other factions, and with enough support, can turn the tide of any battle.