Twilight Harbinger

Enter Dragon Soul and complete the normal mode achievements as early as possible across all bosses, working through Morchok, Yor'sahj the Unsleeping, Warlord Zon'ozz, Hagara the Stormbinder, Ultraxion, Warmaster Blackhorn, Spine of Deathwing, and Madness of Deathwing.

Defeat each Dragon Soul boss on Heroic difficulty — the progression follows a roughly linear path starting with Heroic: Morchok, then Heroic: Ultraxion, Heroic: Yor'sahj the Unsleeping, Heroic: Warlord Zon'ozz, Heroic: Hagara the Stormbinder, Heroic: Warmaster Blackhorn, Heroic: Spine of Deathwing, and finally Heroic: Madness of Deathwing, with difficulty increasing sharply from Blackhorn onward.

Once all required achievements are completed, the Glory of the Dragon Soul Raider meta-achievement will complete and automatically reward the Reins of the Twilight Harbinger directly to your mount collection.