Born Princess Sophia of Anhalt-Zerbst, Catherine is a highly intelligent young woman summoned to Russia at age 14 to marry the heir to the throne. She survives emotional deprivation and isolation by developing a formidable intellect and studying European philosophy. Recognizing her precarious position, she carefully masks her ambition with public submissiveness and learns the Russian language to secure her future.

Grand Duke Peter is the grandson of Peter the Great, brought from Holstein to Russia to secure the Romanov line. He openly dislikes Russian customs and prefers his German heritage. He occupies his time with military drills, playing with toy soldiers, and maintaining a pack of hunting dogs in his private apartments.

The daughter of Peter the Great, Elizabeth seizes the Russian throne in a bloodless coup. She is a powerful autocrat who balances deep religious devotion with a love for elaborate court spectacles. Desperate to secure the Romanov dynasty, she oversees the young court with intense scrutiny and exercises total control over her nephew's marriage.

Gregory Potemkin is an eccentric and ambitious military officer with a talent for theatrical charm. Rising through the ranks of the Horse Guards, he establishes an intense intellectual partnership with Catherine. He acts as a commanding force in Russia's southern expansion and military strategy.

Gregory Orlov is a handsome Guards officer who holds significant sway within the Russian military alongside his four brothers. He provides crucial military backing to Catherine during a period of intense political instability. His popularity among the troops makes him a powerful figure in St. Petersburg.

Nikita Panin is a statesman steeped in Enlightenment philosophy. He acts as a key political advisor who favors institutional reforms and limits on absolute power. He attempts to guide the Russian state toward a more constitutional framework while managing the education of the young Grand Duke.

Paul is the heir to the Russian throne who grows up isolated in the imperial nursery. Developing a strong admiration for Prussian militarism, he often feels excluded from his mother's court. He harbors deep insecurities regarding his position and the nature of his heritage.

Emelyan Pugachev is a Don Cossack who spearheads a massive rebellion against the Russian state. Promising to liberate the enserfed peasants and abolish taxes, he unites disenfranchised groups. His uprising poses a serious military threat to the empire's stability.

Stanislaus Poniatowski is an educated but politically inexperienced Polish nobleman. Introduced to the Russian court as a secretary, he provides Catherine with genuine intellectual companionship. His loyalty eventually draws him into complex international diplomacy.

Johanna is Catherine's ambitious mother, accustomed to the splendor of large German courts. She actively campaigns to secure an advantageous marriage for her daughter. During her time in Russia, she works secretly as an agent for the Prussian king.

Prince Christian Augustus is an obscure German prince who objects to his daughter's required conversion to the Russian Orthodox faith. He provides Catherine with written cautionary advice before parting ways with her permanently.

Bestuzhev is Empress Elizabeth's ruthless and highly capable Chancellor. He maintains strict surveillance over the court and actively intercepts diplomatic correspondence. He prioritizes Russia's security through carefully orchestrated foreign alliances.

The King of Prussia is a shrewd monarch who seeks to counter Austrian influence by cultivating ties with Russia. He manipulates diplomatic channels to advance Prussian interests across Europe. He recruits Johanna to act as a covert agent upon her arrival in St. Petersburg.

Maria Choglokova is Empress Elizabeth's cousin who acts as a strict watchdog over Catherine. Tasked with ensuring the production of an heir, she attempts to control the grand ducal couple's isolation. She dictates who may interact with Catherine on a daily basis.

Sergei Saltykov is an opportunistic court chamberlain from an old noble family. He targets the neglected Catherine upon his arrival as a gentleman-in-waiting. He becomes her first significant romantic entanglement during a period of intense pressure to secure the royal succession.

The English ambassador is a seasoned diplomat tasked with renewing treaties in Russia. He establishes a mentor-like friendship with Catherine, providing her with financial backing. He uses his position to advance British interests while guiding Catherine through European politics.

Alexis Orlov is a forceful Guards officer who operates closely with his brother Gregory. He executes crucial military actions for Catherine's faction. He commands loyalty among the troops and manages the physical custody of political prisoners.

Babet Cardel is a French Huguenot governess who provides primary care for the young Sophia. She teaches her student French language and literature. She instills a lifelong appreciation for European philosophy before the princess departs for Russia.