Land of the Rus

Character-locked: Rurik, 867. Create the Kingdom of Novgorod on day one (which also pops Moving up in the World), convert to the local culture and faith so the de jure neighbours will accept vassalage - gifts help - and spend your once-per-lifetime Subjugation CB on Minsk, then chain Conquer Duchy wars towards the Empire of Russia. Any dynasty member holding the empire counts, so it can span lifetimes. Grim but effective tip from the wiki: Rurik is old, so some players stress-murder him early and continue as his 17-year-old heir for the longer runway.