The Western Church is a religious organization in Fire Emblem: Three Houses. It is an offshoot of the Church of Seiros, with its headquarters located on the border between the Holy Kingdom of Faerghus and the Adrestian Empire. Originally, the Western Church was a regional branch of the Church of Seiros that oversaw western Fódlan, but at some point, its beliefs diverged and it became a separate denomination. Although the Western Church still worships the Goddess, it considers the main Church to be heretical and Archbishop Rhea to be an apostate.
After years of disputes with the Church of Seiros, the Western Church finally escalated tensions into open conflict in Imperial Year 1180. Though they eventually reformed under a new bishop, a radical faction has emerged to resist the new order by moving to seize a sacred cemetery on the Rhodos Coast. The Church of Seiros dispatched Seteth to reclaim the cemetery, but Flayn insisted on accompanying him with Byleth out of fear for his safety.