Emperor Jircniv travels to Nazarick to apologize for the invasion of Nazarick, and is immediately given a show of Nazarick's power when they use Tier 6 magic easily, and use Death Knights, monsters capable of slaughtering armies for menial tasks like setting tables. Ainz further shows off his power, when he is given the head of the noble who was responsible for sending Workers to Nazarick (albeit, secretly on Jircniv's orders) and turns it into a Death Knight...