Each week, one of the three major Orders that make up the Pact will send an emissary to the Eye of the North with a chest for you. Complete the daily Priority Strike found in the Daily section of the Achievements tab to earn a Prophet Crystal that can be used to open the chest once per week. The chest resets at the same time weekly raid rewards reset.
In addition, you can get echoes of rewards from the new Forging Steel Public Mission if you complete it before opening the chest.
The Emissary Chest will open if you possess one crystal—but more crystals produce stronger echoes. Opening it with three crystals is equivalent to earning two bonus chests in a Strike Mission. Opening it with two crystals is equivalent to earning one bonus chest, and one crystal is equivalent to earning the basic mission rewards. All Strike Missions also award Prophet Shards you can use to purchase whole crystals and other rewards.
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