Gwigongja

Jin Tae-Ha, the successor to Korea's leading conglomerate Cheongu, is the only survivor of a terrorist attack while on a yacht trip with his family. Jin Tae-Ha learns that his family was murdered not by accident but by a power struggle among his relatives, and joins the Italian mafia Salerno Family to prepare for revenge. After 17 years, he returns to Korea and finally begins his revenge

(Source: Naver, translated)