Adjudicate The Arbiter

Adjudicate The Arbiter is an Achievement in Halo Wars that is unlocked when the player completes the Campaign on the Heroic difficulty.

It is worth 30 Gamerpoints.

Trivia

 * The achievement seems to be a judge's mallet hitting the Arbiter's head.
 * To adjudicate means to judge, or come to a verdict, hence the presence of the mallet.