Vengeance Pact
The Vengeance Pact was the binding agreement among the Alethi highprinces that launched their long war against the listeners, or Parshendi, on the Shattered Plains in Brandon Sanderson's The Stormlight Archive.
Origin
The pact was sworn after the assassination of King Gavilar Kholin of Alethkar. On the very night that Gavilar and the listeners signed a treaty, a listener assassin, Szeth, killed the king. The listeners openly claimed responsibility for the murder, an act that stunned the Alethi court.
The pact
In response, Gavilar's brother Dalinar Kholin and the other Alethi highprinces swore the Vengeance Pact, a collective oath to pursue the listeners and avenge the slain king. The Alethi armies marched east and laid siege to the listeners' refuge on the Shattered Plains, beginning a war that would last for years.
Consequences
The Vengeance Pact transformed Alethi society, drawing the highprinces and their armies into a protracted plateau-by-plateau campaign on the Shattered Plains, driven as much by the contest for chasmfiend gemhearts as by the original vow. The war forms the backdrop for the opening of The Stormlight Archive, and its eventual collapse, as the true threat of Odium becomes clear, reshapes the alliances of Roshar.