A blood feud refers to a prolonged conflict between two families or groups that typically involves revenge, violence, and a desire to seek justice for past wrongs. Full definition
3) The 24/7 Sunni - Shiite centuries - old blood feud currently being carried out in Iraq, US Troops killed in action, 3,481 and 924 died in non-combat, 97,172 — 106,047 Iraqi civilians killed by Shiite and Sunni suicide bombers following verses from the koran (religion.blogs.cnn.com)
In societies without lawyers, disagreements result in blood feuds, gang wars, and revenge killings. (dlalaw.com)
The original Sonic The Hedgehog hit the Mega Drive back in 1991, as an attempt to give the Mega Drive a «must own'title, as well as establishing a mascot for Sega to use in their intense Oriental blood feud with Nintendo (Spoiler — Nintendo won. (gamesrevisited.com)