Command Mode is a special skill used to command other party members in the field. This command applies to only the mercenaries and Calista; special characters like Horace and Asthar cannot be commanded (with the brief exception with Horace whenever he assists the party). Command Mode uses the Command Gauge, which is the shining blue gauge in the top right corner next to the leader's HP Gauge.
Command Mode is an unlockable skill obtained by starting Chapter 11. Command Gauge starts off empty, but over time, it will replenish.
Command Mode also lets the player use the party members' Spirit Attacks, as well as assign them to use their secondary skill. If Zael uses Gale (his secondary skill), it will deplete on bar of the Command Gauge as well as pause its replenishment for a short time.