On the latest Patch 9.2 PTR build, the requirements for flying in Zereth Mortis have been changed. A new achievement was added, and it should take 2 weeks to earn Zereth Mortis flying! The new achievement added to the 9.2 PTR is Unlocking the Secrets, which requires you to complete certain tasks around Zereth Mortis. Below we have a breakdown on all the achievements.
TL;DR version: All achievements but A Means to an End can be obtained not long after stepping foot in Zereth Mortis. That last achievement requires doing the 9.2 Campaign and should be obtainable at Week 3 of Patch 9.2.
Explore Zereth Mortis: Explore Zereth Mortis, revealing the covered areas of the world map. Standard explore the full zone achievement.Achievement does not require exploring the Sepulcher of the First Ones raid island (which is locked behind a teleporter that becomes active on Week 2 of Patch 9.2), so this achievement is completable day 1. Curious Collections: Discover 5 hidden treasures of Zereth Mortis. Loot 5 of the one-time treasures from Zereth Mortis.
Looting 5 treasures is easily doable day 1, you can check the achievement Treasures of Zereth Mortis for a full list of locations and requirements. Path to Enlightenment: Complete 3 side questlines in Zereth Mortis. All 3 sidequests should be available day 1, after completing Chapter 3 of the Campaign, Forming an Understanding:Small Pet Problems starts with the quest Look Who I Found! in Haven; Not Al Are Lost starts with the quest Enlightened Exodus in Haven; The Waters of Grace starts with the questLost Grace in Pilgrim's Grace.
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