5. Kim Il-Sung
Kim Il-sung ruled North Korea with absolute control, building a strong cult of personality and enforcing strict isolation through the Juche policy. His role in the Korean War left the peninsula divided and caused millions of deaths. His regime was marked by brutal labor camps and severe repression. A devastating famine in the 1990s led to the loss of millions more lives. Though he died in 1994, his harsh legacy continues through his successors.