The Marine faction is located at an archipelago away from the mainland that all the other traditional factions call home. The home terrain is sea (and water in general) as well as jungle (for the islands). Marine units are equally adept at walking, swimming and flying. One of the main themes of the faction is versatility, travel, adventuring.
Another prominent theme is storms. Located far out in the ocean, the islands are no strangers to fickle weather, both air and sea-borne. Magically-inclined creatures have learned to harness the power of storms, which is well represented in the devastating spells that are available to them.