The Vengeance Pact was a pact between the ten Highprinces and King Elhokar Kholin. It's main goal was to take vengeance on the Parshendi after the apparent assassination of King Gavilar by their order.
After having met Parshendi in the region where the Shattered Plains are located, Gavilar started to establish diplomatic relations with the Parshendi. This lead to an invitation of Parshendi to Kholinar in Alethkar to celebrate the signing of a treaty between Alethi and Parshendi. On that night, the Assassin in White killed King Gavilar. The Parshendi took credit for that assassination and fled from Kholinar.
The Highprinces and King Elhokar then made the Vengeance Pact.
 War against the Parshendi
After the assassination of King Galivar, the Parshendi retreated to a plateau in the middle of the Shattered Plains, where they established their camp. The ten Alethi warcamps, as well as the king's camp are situated on the west of the Shattered Plains. Despite their larger numbers, a full-scale attack against the Parshendi camp by the Alethi forces was not possible because of the Highstorms that made it impossible to survive exposed on the Shattered Plains. Because of this, the Alethi decided to settle for a siege. What followed was called the War of Reckoning.
 The impact of gemhearts
When arriving at the Shattered Plains, the Alethi armies came upon huge beasts, called chasmfiends that lived in the chasms between the plateaus that form the Shattered Plains. Like all Roshar-originated animals, chasmfiends had gemhearts that were among the largest gems known on Roshar and were therefore of immense value. The only way to safely get at the gemheart was to harvest it when the chasmfiend was pupating. The chasmfiends climbed on a plateau in order to do this. The Alethi and the Parshendi both tried to gain as much gemhearts as possible. That's why a race started everytime a pupating chasmfiend was spotted between the Parshendi on one side and the Highprinces on the other side to get to the plateau first. Whoever arrived first was usually attacked by the other.
Although gemhearts were essential for the warfare in that they were used to Soulcast barracks, wood and food, the battle for gemhearts changed the original purpose of the Vengeance Pact. The Highprinces fought not for vengeance but for gemhearts. It was not until Dalinar joined forces with Sadeas that two Highprinces worked together to get a gemheart. After being named Highprince of War, Dalinar planned to change tactics and fulfill the Vengeance Pact again instead of only harvesting gemhearts. It has been noted by Brandon that over-harvesting of gemhearts may cause environmental damage. [Clarification needed]
|History of Roshar|
|Assassin in White||Vengeance Pact||Attack on the Tower|
|The Stormlight Archive (Roshar)|
|Books||The Way of Kings · Words of Radiance · Stones Unhallowed · The Highprince of War|
|Major Characters||Kaladin · Shallan · Szeth · Dalinar · Navani · Adolin · Jasnah · Elhokar · Sylphrena · Taravangian · Kabsal · Sadeas · More Characters|
|Shards||Honor · Cultivation · Odium|
|Magic||Stormlight · Highstorm · Surgebinding · Shardblades · Soulcasting · Fabrials · Ten Essences · Old Magic · Voidbinding|
|Creatures||Chasmfiend · Greatshell · Parshmen · Parshendi · Spren · Thunderclasts · The Unmade · Voidbringers|
|Places||Alethkar · Jah Keved · Kharbranth · Shinovar · Purelake · Silver Kingdoms · Urithiru · Shattered Plains · The Origin · More Places|
|Groups||Bridge Four · Heralds · Highprinces · Knights Radiant · Ghostbloods · Vorinism|
|History||Desolations · Oathpact · Day of Recreance · Hierocracy · War of Reckoning|