Jered Cain assisted Tal Rasha with the imprisonment of Mephisto and Baal. After Baal's soulstone was shattered, Tal Rasha contained Baal within himself and Jered led the Horadrim further West into Khanduras to pursue Diablo.
Jered captured Diablo in Khanduras and imprisoned him inside the last soulstone. Under Jered's leadership, the Horadrim placed Diablo's soulstone at the bottom-most part of a system of caves under the town of Tristram, and erected a Horadric monastery above it. Jered stayed to watch over the town, the soulstone, and the new monastery.