From WoWWiki
Crusaders' Square is located inside Stratholme Scarlet Side, west from Market Row. It is the location of the Scarlet Bastion, and is also where players have to do battle against Timmy the Cruel. Numerous members of the Crimson Legion attempt to defend their holdings here, behind crates and rubble.
Crusaders' Square in Old Stratholme can be found west from Market Row. Talking to Arthas for the final time will begin the fight with Mal'Ganis. When defeated the Dark Runed Chest will appear as will Chromie.
