Leader

For more use of "Hero", see the disambiguation of Hero. Leaders, sometimes called Hero units, are UNSC, Covenant, and Banished combat personnel Halo Wars and Halo Wars 2 who are suited to lead infantry, ground vehicles, and aircraft.

Halo Wars overview
Leaders offer a varied experience in Halo Wars ' multiplayer aspects, bringing unique abilities into the fray. The Covenant have leaders that double as in-game units while the UNSC leader powers vary greatly and are numerous.

In campaign, they also can be revived if they are killed in action, as long as the life bar is halfway full. The life bar automatically regenerates while the leader is knocked down. However, in Skirmish or multiplayer if they die they die for good and will have to be purchased again to be on the battlefield, though only Covenant hero units are present on the battlefield in Skirmish and multiplayer.

Captain Cutter
Similar to his abilities in Halo Wars Cutter focuses on troop deployment and orbital support.

Atriox
Atriox focuses on economic abilities.

Combat experience
Hero units are more adept to fighting, possessing more armor for protection against the enemy units as well as access to unique weaponry and "special abilities" (such as "Rage mode" for the the Arbiter or special upgrades like the ODSTs for Captain Cutter).

Against the AI on skirmish, their hero unit of choice impacts on their playstyle. For instance, Cutter is more "measured" while Forge's playstyle is quite aggressive.

Trivia

 * In the Halo Wars Demo, Captain Cutter was the only available hero unit for the UNSC and the Prophet of Regret was the only available hero unit for the Covenant.
 * In the Halo Wars 2 Open Beta, Captain Cutter and Atriox were the only leaders available.