In the newly revamped Blackrock Depths raid, players can earn the achievement A Dark Iron Past by finding temporal missives from Moira Thaurissan detailing the troubled history of the Dark Iron dwarves.
Alongside the updated boss mechanics and current-tier loot, each boss room on the path to Dagran Thaurissan has an orb situated nearby, which plays a message from present-day Moira Thaurissan showcasing her thoughts on the actions of her people back during vanilla WoW.
Temporal Missives Detention Block This missive can be found after defeating Lord Roccor, near the old entrance to the Detention Block.
Moira Thaurissan says: The Dark Iron dwarves enslaved many tae work in their mines and supply the war machine. Moira Thaurissan says: When there weren't enough workers left, they sent their fellow Dark Iron instead...
Twilight's Hammer This missive can be found at the initial entrance to the Dark Iron Highway, after defeating High Interrogator Gerstahn.