New Ascendant Challenge Location – Powerful Engram Reward – Solo Ascendant Challenge.
To make the Ascendant Challenge, you first need a "Tincture of Queensfoil". These come as random drops from each chest in the Dreaming City, including region chests.
After that, head Bay of Drowned Wishes - the Lost Sector in Divalian Mists. It involes a series of jumps going down very deep, and once you reach the bottom arena a bunch of Taken Blights will spawn, along with yellow-bar Wizards. Killing the Wizards completes the challenge.