This DLC adds "Nitori (UNK教祖)" to Nyanco Desktop Mascot.

How to set or change the DLC mascot you want :

• Find images in the DLC folder for the mascot character
  
• Copy and paste them into the images folder
  
• Close the app and restart it

How to find the DLC folders of this app :

Steam Client -> Right-click the app -> Properties -> Local Files -> Browse

How to close the app :

• Click the mascot and press the “ALT + F4” keys at the same time
  
• You can also close the app by pressing the "STOP" button located on your Steam client.

Disclaimer :

The mascot character, "Nitori (UNK教祖)" included in this DLC isn't related in any way to the original Touhou Project.