The Reins of the Slate Primordial Direhorn are a rare drop from the elite blue-eyed Zandalari Warbringers that spawn on the coast of Jade Forest, Krasarang Wilds, Kun-Lai Summit, Townlong Steppes, and Dread Wastes. It can also be listed on the Black Market Auction House.
Here you can buy Slate Primordial Direhorn for EU or US Servers.
You'll get guide for getting Slate Primordial Direhorn
You'll be able to get Slate Primordial Direhorn
Slate Primordial Direhorn mount
Additional budget for Character transfer or Character boost to max level. BMAH Services in Shadowlands now requirement to have a max level character on server, so Trial character will not work.
Free time on evening, if you choose selfplay option