Maniacal /məˈnʌɪək(ə)l/ adjective exhibiting extremely wild or violent behaviour. "a maniacal dictator" ARCHAIC•PSYCHIATRY suffering from mania. "maniacal patients" Min Yoongi's father, Kim Junmyeon used to be the leader of the Korean mafia. On Yoongi's 21st birthday Junmyeon sends his son on a mission; Take back what was rightfully his.