North Korea
Kim Jong-un of the Kim dynasty is the current Supreme Leader or "Suryeong" of North Korea. He heads all major governing structures: he is Chairman of the Workers' Party of Korea, Chairman of the State Affairs Commission of North Korea, and Supreme Commander of the Korean People's Army. His grandfather Kim Il-sung, the founder and leader of North Korea until his death in 1994, is the country's "Eternal President", while his father Kim Jong-il who succeeded Kim Il-sung as leader was announced "Eternal General Secretary" after his death in 2011.
Purge
North Korean leaders Kim Il-sung, Kim Jong-il, and Kim Jong-un have each periodically purged their political rivals or perceived threats, beginning in the 1950s. The most senior Kim purged those who opposed his son's succession to the supreme leadership of North Korea. Kim Il-sung's most prominent purge occurred during the "August Incident" in 1956, when the pro-Soviet and pro-Chinese Yanan factions of the Workers' Party of Korea (WPK) attempted to depose Kim. Most of those involved in the plot were executed while some others fled to the USSR and China. While some purges were carried out under Kim Jong-il, they were not as common as they were under his father/son. Kim Jong-un purged a number of high-ranking officials and generals installed by his father Kim Jong-il in the former's first years in power, including, most prominently, his uncle Jang Sung-taek.