Short answers, pulled from the story.
Nicholas I of Russia began his reign on the 1st of December 1825 following a manifesto issued on the 25th of December. The Decembrist revolt occurred on the 14th of December 1825 when he ordered the Imperial Russian Army to fire into a crowd of three thousand people.
The Third Section of the Imperial Chancellery employed three hundred gendarmes and sixteen staff members to run a vast spy network starting in 1826. Mail interception became routine practice under this office which monitored citizens so thoroughly that rumors claimed it was impossible to sneeze inside one's house without the emperor knowing.
Colonel officers pocketed their men's pay and sold off the best equipment and food supplies while musket quality suffered due to prioritized personal profit. Sixty-one percent of Nicholas I of Russia ministers had previously served as generals or admirals yet only fourteen held university degrees leading to catastrophic failures in both domestic and foreign policy.
Persia was forced to cede its last remaining territories in the Caucasus including modern-day Georgia Dagestan Armenia and Azerbaijan through the Treaty of Turkmenchay. This treaty granted Russian control over these regions following the war that concluded in 1828.
Nicholas I of Russia died on the 2nd of March 1855 at the Winter Palace in St. Petersburg during the war. He caught a chill and refused medical treatment dying of pneumonia according to official records though rumors suggested he committed passive suicide by refusing care.