Skirmish

Looking for Skirmisher, a group of Kig-yar shock troops introduced in Halo: Reach?

Skirmish is a mode in Halo Wars and Halo Wars 2 which allows the player to battle against 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, leaders, game modes, difficulty levels, and the map. In Halo Wars skirmish may be played in Standard, Deathmatch mode. Downloading the Strategic Options DLC adds three more modes: Keepaway, Tug of War, and Reinforcements.

Halo Wars teams
There are three leaders each for the UNSC and the Covenant. The player can choose leaders for himself and for any A.I. opponents by selecting a slot on the Alpha or Bravo Team. Also, a random team leader or both random faction and leader can be selected.

Each character the player pick has his/her own special offensive abilities and upgrades, and each UNSC leader has a special economic bonus.