Reins of the Long-Forgotten Hippogryph is a new mount that was added with Legion. How to obtain this mount was shrouded with mystery until now. To get the mount we will have to delve deeper into Azsuna, one of the zones on Broken Isles.
How to Obtain the Mount
To obtain the mount, you will have to click the five Ephemeral Crystals located in Azsuna within 8 hours in no specific order. The first person to click the crystals will see the mount added to their inventory. After a person obtains the mount, the crystals will disappear for an unknown time (reports estimate anywhere between 3 to 8 hours). Note that all of the crystals are located in Azsuna.
Locating the Crystals
Here's a map of all the crystal locations. Upon clicking a crystal you will be given a buff called Crystal Dummy Aura 1 - 5. Upon clicking the fifth crystal, you will see the mount reins appear in your inventory.
Details on the Ephemeral Crystals are below, I've included location and coords.
1. The first crystal is located in Academy North Wather [54, 33]
2. The second crystal can be found in Wellspring [37, 32]
3. The third Ephemeral Crystal is located in Azure Cave [50, 20]
4. Greenway Imp Cave [61, 30] is the location for the fourth crystal
5. The fifth and final Ephemeral Crystal can be found in Ozeanus Cove [47, 62]
Happy farming and good luck getting your mount! Again, make sure to check out the spots before doing this as you need to be the first to click them all. There will be lots of farming in the coming days, but don't give up! If you happen to encounter difficulties, refer to the screenshot depicting all locations highlighted on the Azsuna map!