|Each character in the game has a unique item they can unlock if certain requirements in various stages are met. I will be detailing Zhou Yun's as it is the one I got and it wasn't too hard. While their might be an easier one out there I will be listing this one as it's the only one I know how to get.|
It is done on Shu Story Mission chapter 7
You have 10 minutes to accomplish the following: Defeat Zhang Fei, Guan Yu, go to the 3rd floor defeat the three officers to initiate the fire attack, and defeat 100 enemies.
If you are successful a message will show up telling you a unique item has appeared. To find it, pause the game and look at your map. See the garrison in the bottom right hand corner. From there look northwest and there you should see an enemy spawn point with a red flag. The item will appear just outside that area. It is in a box with funky colors and designs on it (you'll know it when you see it). Another tip to help you locate it: When the message appears look at your on screen map there will be a flash of white circles at the location of the item.