Judge Grey was hired as an arbiter to settle the dispute between AvLee and Erathia. He told the Lords of Harmondale that he didn't particularly care who won, as he considered both nations to be "like children fighting over a toy."
When the party recovered Gryphonheart's Trumpet, a powerful symbol from a previous dispute between the two nations, they presented it to the Arbiter. Judge Grey thanked them for their trust, and used the artifact to promote peace in the bitter struggle.
Judge Grey died of a heart attack a few months into the conflict. The two nations declared a truce, and asked the Lords of Harmondale to find a replacement for him. In the end, the party chose Judge Fairweather for the task.
Judge Grey can be found in the House of Stars in Harmondale. If the party loses any quest items, they can get them back from him. He also gives the party advice about what to do next.
Judge Grey plays a part in the Retrieve Gryphonheart's Trumpet quest. The party can give Gryphonheart's Trumpet to King Parson or Queen Catherine to have Harmondale come under the rule of AvLee or Erathia, respectively, or they can give it to Judge Grey to have Harmondale decome an independent state.
Judge Grey dies a few months into the conflict, which starts the Choose an Arbiter quest.
Judge Grey appears in Might and Magic VII: For Blood and Honor.