Erik Vasa began his rule not as a conqueror, but as a puppet installed by foreign overlords to manage a broken nation. Following the Polish-Swedish Union's invasion of Russia in 1605 and the subsequent scorched-earth destruction of Moscow by the fleeing Tsar Shuysky, the Union sought to stabilize the region under a pliable figurehead. Elected by a coerced Zemsky Sobor in September 1605, Erik, a nephew of the Polish-Swedish King, ascended the throne of a realm that was effectively a failed state. His early reign was defined by his total lack of agency; his army answered to foreign generals, his administration was run by Polish officials, and the resources of his starving, war-torn realm were ruthlessly extracted to feed the Union's population, leading to widespread famine and resentment.

Confronted with the visceral hatred of his subjects and the realization that he was ruling over a "wasteland," Erik underwent a profound personal and political transformation. Refusing to remain an isolated foreigner, he dedicated years to learning the Russian language and immersing himself in the local culture. This process opened his eyes to the deep embarrassment and resentment the Russian people felt toward their occupiers. Realizing that true legitimacy could only be achieved by shedding his foreign veneer, Erik "went native," slowly wresting administrative control back from Union officials during the distraction of the Ten Years' War in the 1640s. He began to deceive his overlords, falsifying tax records to keep resources within Russia and quietly rebuilding the state's internal strength.

The culmination of Erik’s metamorphosis occurred when he sought an alliance with Eastern Rome to secure Russia's independence. Accepting Constantinople's condition that a true Tsar must share the faith of his people, Erik publicly renounced Catholicism and converted to Orthodoxy in June 1646, an act that severed his final ties to the House of Vasa and branded him a traitor in the eyes of Warsaw and Stockholm. Seizing the opportunity provided by the ongoing continental chaos, he declared war on his own homeland in February 1648. Leading a rejuvenated, albeit scarred, nation against its oppressors, Erik Vasa successfully shattered the Polish-Swedish yoke, transforming from a foreign puppet into the founder of a resurgent, independent Russian Empire.