After you complete the Northrend quest “The Aspirant’s Challenge” as an Evoker/Dracthyr, you do not get a follow up quest to continue with the next set of quests. Usually the follow up will be to follow up with “The Valiant’s Charge” with your respective race’s champion.
Void elves will champion with Darnassus, and Pandaren will champion with Org/Stormwind as an example. Dracthyr currently are locked out after completing the first quest.