here is a quick list of those responsible for killing over one million people each
Mao Ze-Dong (China, 1958-61 and 1966-69, Tibet 1949-50) 49-78,000,000
Jozef Stalin (USSR, 1932-39) 23,000,000 (the purges plus Ukraine's famine)
Adolf Hitler (Germany, 1939-1945) 12,000,000 (concentration camps and civilians WWII)
Hideki Tojo (Japan, 1941-44) 5,000,000 (civilians in WWII)
Ismail Enver (Turkey, 1915-20) 1,200,000 Armenians (1915) + 350,000 Greek Pontians and 480,000 Anatolian Greeks (1916-22) + 500,000 Assyrians (1915-20)
Pol Pot (Cambodia, 1975-79) 1,700,000
Kim Il Sung (North Korea, 1948-94) 1.6 million (purges and concentration camps)
Menghistu (Ethiopia, 1975-78) 1,500,000
Yakubu Gowon (Biafra, 1967-1970) 1,000,000
I am sure that these 126,330,000 people would like to know where these higher intelligences where as they where being killed.
none of these killings involved nukes, they used rather primitive weapons by todays standards.