Ivan the Terrible is one of the secondary antagonists in Night at the Museum 2. He was one of the villains that joined forces with Kahmunrah.
Night at the Museum 2
Ivan the Terrible along with Napoleon Bonaparte, Al Capone and their henchmen (gangsters, Streltsi and hussards), joined Kahmunrah. They don’t really see what the point is, but they understand they will be given a part of the world in exchange of their help.
Ivan later returns to Kahmunrah along with two fictional exhibits (Darth Vader and Oscar the Grouch) and they tell Ivan that they like to rule the world as well, but Ivan doesn't know who they were.
Ivan sends his henchmen to bring back the Tablet from Larry and Amelia after Kahmunrah thinking they were trying to flee.
Later Ivan along with Napoleon Bonaparte, and Al Capone went to find Larry and Amelia and they find in the Air & Space Museum, but they fail in the pursuit.