Final answer:
After Ivan the Terrible, his son Fedor I became the Tsar of Russia, and his ineffective rule led to the Time of Troubles.
Step-by-step explanation:
The leader who emerged after Ivan the Terrible in Russia was his son, Fedor I, who became the ruler following Ivan IV's death in 1584. Fedor I's reign was markedly less effective due to his poor health and intellectual disabilities, leading to the eventual establishment of the Time of Troubles, a period of political crisis and social unrest.
However, he was officially Tsar until his death in 1598, after which the Rurik dynasty came to an end, and the Romanov dynasty eventually took power.