Final answer:
The Russian leader who repressed serfs after they were given some freedom was Alexander III, following the assassination of his father, Alexander II, who had emancipated the serfs in 1861. Alexander III reintroduced autocratic policies similar to those of Nicholas I, which included increased use of secret police and censorship, as well as a policy of Russification to suppress non-Russian cultures.
Step-by-step explanation:
The Russian leader who cruelly suppressed the serfs after initially giving them some freedom was Alexander III. Alexander II was the one who emancipated the serfs in 1861, following Russia's defeat in the Crimean War. His aim was to modernize Russia and eliminate the backwardness associated with serfdom.
However, this freedom came with a price, as the serfs incurred a debt to the government for the land they were to buy from the nobility. After Alexander II was assassinated, his son, Alexander III, ascended to the throne and reversed many of the reforms, reinstating the autocratic and oppressive measures of Nicholas I. These measures included increased use of the secret police, censorship, and the policy of Russification, suppressing non-Russian cultures within the empire.
The rebel groups had issues with the tsarist government because of the lack of political freedom and the oppressive measures against various ethnic groups and political dissenters. Their goal was to catalyze a massive uprising that would lead to a transformation of Russian society, inspired by anarchist socialist ideas. However, Alexander III's reactionary policies after his father's assassination only intensified the suppression of freedoms, making it harder for rebel groups to achieve their end.