Feud
A blood feud is a feud with a cycle of retaliatory violence, with the relatives of someone who has been killed or otherwise wronged or dishonored. The wronged person then wants vengeance and kills the culprits or  punishes them in other ways. If he cannot get the culprits, he does this to their relatives. Historically, the word vendetta has been used to mean a blood feud. The word is Italian, and originates from the Latin vindicta, "vengeance." In modern times, the word also means any other long-standing feud, not necessarily involving bloodshed.