Doctor Zeiger was sent to Blackstone to care for rabbits during a flu epidemic. Some time later, soldiers from Blackstone accompanied Lord Ronan to Cloud Mountain for a Citadel Congress. This citadel was very against all Longtreaders, to the point that Lord Ronan did not want to be in the same room with Wilfred or any Longtreader.
According to Jo Shanks, there was a close bond of friendship between Blackstone and Halfwind Citadels, both holding the Longtreaders under suspicion. A soldier from Blackstone also identified Heather Longtreader after hearing Jo ask about her. Captain Brone of Blackstone also passed word of wolf patrols in the surrounding forest to Captain Frye. The forces from Blackstone were caught up in the attack on Cloud Mountain, and subsequently pursued the retreating wolf invaders.
Blackstone Citadel was the most stubborn holdout against both accepting the Longtreader family as heroic members of the cause and recognizing prince Smalden Joveson as King Jupiter's heir. As a result, an invitation was sent to Lord Ronan to attend a conference at Kingston, though this meeting ultimately never occurred. When Halfwind Citadel learned of the approaching Terralains, the leaders resolved to send a message to Blackstone as a sign of their regarding that citadel as an ally.
As Emma, appointed Jupiter's heir in the wake of her brother Smalls' apparent death, made her tour of various citadels, Blackstone was among those she visited. On the advice of Heyna Blackstar, she adjusted her travel schedule in order to reach Blackstone much earlier than anticipated. This was designed to unsettle Lord Ronan, who remained suspicious of the Longtreaders and her own claim to the throne. As a result of this tactic, Blackstone's loyalty was secured, and their forces took part in the Battle for First Warren.
- As of the end of Ember Rising, Blackstone is one of only two secret citadels-the other being Kingston Citadel-in which no scenes from the series have taken place. It is also the only citadel not to have any named personnel featured in any scenes.
- The name "Blackstone" is of English and American origin.