Other computer controlled characters join you on your quest. Depending on your preferences or types of tactics, these characters can be tweaked by the types of weapons or armor you equip them with.
The "Action" portion of this RPG is that all battles are done in real-time. Think a Gauntlet type of hack and slash. Your battles may include killing numerous monsters or monster machines which will continue to spew new creatures until you put an end to their usefulness.
An interesting addition to the genre is the "Geo-Fortress." This castle is your home base, where you train as well as lodge your party members while they are not joining you on missions. Enemies may attack the Geo-fortress in your absence, so not only do you have to worry about what characters you bring with you, but you also the people you leave behind making sure your castle is properly defended. Similar to how characters level up through out the game, finding "precious metals" will allow you to upgrade the Geo-Fortress with new abilities and improved defenses, going from mountain-top keep to castle in the sky.
Shining Force EXA is due for release in the US this March. Expect your social life to be put on hold for the next 30-50 hours of game play.