Haha, that means Ostrava (the knight you saved) died because he drops that key. The blue eye knight probably killed him, he gives you more rewards if you rescue him in the later levels. Oh well, at least you found the key before you went back to the Nexus, would have lost it for the playthrough and wouldn't have been able to fight Doran and get the Demonbrandt if you hadn't found that key.
XI Wiki



