There is a bitter, destructive and escalating feud between two factions within one society.

Examples:
Yuta of the vanquished clan Tralesta was genetically altered and spent 100 years tracking down members of the Lornak clan in a vendetta in tng3x09 "The Vengeance Factor".

Aliases:
blood feud

References:
https://en.wikipedia.org/wiki/Feud