Midnight Season 1 Mythic+ Overview
Victor Achievements
These achievements were datamined back in the Midnight Beta and might be available with the launch of Midnight Mythic+.
NEW Attain a region-best keystone dungeon completion for Algeth'ar Academy.
NEW Attain a region-best keystone dungeon completion for Magisters' Terrace (Midnight).
NEW Attain a region-best keystone dungeon completion for Maisara Caverns.
NEW Attain a region-best keystone dungeon completion for Nexus-Point Xenas.
NEW Attain a region-best keystone dungeon completion for Pit of Saron.
NEW Attain a region-best keystone dungeon completion for Seat of the Triumvirate.
NEW Attain a region-best keystone dungeon completion for Skyreach.
NEW Attain a region-best keystone dungeon completion for Windrunner Spire.
What's interesting about these achievements is that there's no mention of the achievement being rewarded at the end of the season. This would imply these achievements will operate similarly to the Mistwalker achievements introduced back in Mists of Pandaria.
Based on the wording, there are a few ways this achievement could work. It's possible that they could be one-and-done, like Realm First leveling achievements were, or many teams could achieve them over time:
Awarded to those who are the first in their region to complete a keystone. No future teams can earn the achievement.
Awarded to those who beat the previously established region-best time.
Awarded with each varying keystone level.
If this achievement is available with the launch of Mythic+, the easiest chance at getting the achievement is right when the servers come up after maintenance. Keep in mind, though, that these achievements may not be implemented at all - not everything datamined makes it to live servers.
