Skirmish

From Halopedia, the Halo Wiki

Skirmish is a mode on Halo Wars which allows the player to battle against other opponents, either human or A.I., on various maps and under a variety of conditions. The player can select the number of opposing A.I teams, Leader types, modes, difficulty levels, and the map. Skirmish may be in Standard or Deathmatch mode.

[edit] Teams

There are three Leader types for the UNSC and the Covenant. They can be chosen from the Leader Selection Menu for yourself or for A.I. opponents by selecting a slot on the Alpha or Bravo Team. Also a random team Leader or both random can be selected.