This information is not confirmed and only my thoughts.
After completing the Suramar questlines (Suramaritan and Insurrection) and doing some extra research, my conclusion is:
- You need to complete the Achievement “Good Suramaritan”.
- You need to complete the Achievement “Insurrection”.
- You need to complete the quest: “Lord of the Shadow Council” which you obtain from Khadgar after completing the Insurrection questline.
This quest is to kill Gul´dan in the Nighhold raid.
- Finishing the Nighthold raid (completing “Lord of the Shadow Council” quest) will give you new quests (and the quest “Fate of the Nightborne”) and maybe some cool cinematics ending with that you obtain the mount Arcanist´s Manasaber.
- Blizzard mention this mount in 7.1 info. Does that mean Nighthold will be part of 7.1 (.X) or 7.2? we have to wait and see.
What we do know, that is confirmed so far
The only real information of how to get this mount is:
- Complete the Questline/Achievement “Insurrection”
“If you follow the quest line to completion, you’ll be much closer to obtaining the wondrous new Arcanist’s Manasaber mount.”
- Complete the quest: Fate of the Nightborne
According to the Mount collection tab, you must complete the quest “Fate of the Nightborne”.
Also, on the description it says that you helped First Arcanist Thalyssra to liberate Suramar and therefore getting the mount as a reward.
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