Short answers, pulled from the story.
Louis XIV of France declared that he was the state while reigning from 1643 until his death in 1715. This statement encapsulated the terrifying reality of absolute monarchy where the sovereign is the sole source of political power.
Russia became the last European country to abolish absolutism as late as the 20th century. The Romanov dynasty ended in 1918 when the Bolsheviks executed the Romanov family after ruling for three centuries.
As of 2023, Vatican City has a population of 764 residents regardless of citizenship. This makes it the smallest state in the world both by area and by population.
Current datasets agree that Brunei, Eswatini, Oman, Qatar, and Saudi Arabia are absolute monarchies. Some datasets also include Bahrain, Bhutan, Jordan, Kuwait, Liechtenstein, Monaco, Morocco, Samoa, Tonga, Vatican City, and the United Arab Emirates.
Charles I ruled without Parliament for 11 years starting in 1629 to dissolve the body that might have checked his power. His attempt to enforce episcopal polity on the Church of Scotland led to rebellion by the Covenanters and the Bishops' Wars.
The Nepalese monarchy was abolished on the 28th of May 2008. This event followed several swings between constitutional rule and direct rule related to the Nepalese Civil War and the 2001 Nepalese royal massacre.