Rivendark

Rivendark is a black dragon that flies over the Vortex Pinnacle in the Blade's Edge Mountains. Be very careful around Rivendark — if he detects you he will spit a fireball at you. (~3000 damage)

As of patch 2.4.2, the dragons in Blade's Edge Mountains no longer instantly knock you off your flying mount.

Rivendark can be called down at any time by opening Rivendark's Egg at Rivendark's Perch (requires 35 Apexis Shards. When summoned, he lands and attacks the party.

Loot
Rivendark drops a variety of items, usually a depleted rare item, Dragon Teeth and the Onyx Scale of Rivendark.