Halo Wars 2

This achievement will likely come naturally while playing online matches as The Arbiter, but it can be done quickly in solo Skirmish matches against the AI on Easy. If you're taking this route, head into the Skirmish lobby and make these setting changes:

• Gametype: Domination
• Starting Supply: 9999
• Starting Power: 9999

Now choose any small map (Badlands or Sentry) and make sure you pick The Arbiter as your leader before initiating the match. Once the match starts, build a War Council; once it is complete, summon The Arbiter.

When The Arbiter arrives on the battlefield, select him with your cursor and then move out to any of the Power Nodes around the map. The Sentinels guarding the Nodes will begin attacking your Hero unit, so quickly tap to activate Rage and then attack the Sentinels with . You should be able to eliminate all three-to-four hostiles within one duration of Rage.

Continue to utilize this method throughout the match against the Sentinels guarding other Power Nodes. It may take two or three matches to get this done, but it will go quickly regardless (you can quit out of a match once there are no more Sentinels to kill). Once you have killed twenty Sentinels with the Arbiter while raging, this achievement will unlock.