And you can do that thanks to a tool which transfers a CK3 world into Europa Universalis 4, picking it back up in the Paradox grand strategy game set in the following era. What to do when you've completed a Crusader Kings 3 campaign? You could start over as a new ruler in a new place, I suppose, but isn't that negligent? A truly responsible leader would steer their nation through the middle ages, the Victorian era, and World War 2.