Diendran Abbey, also known as Tereo Church, is the only church in the village of Tereo. The abbey lies adjacent to the village square and consists of a single stone building with iron-bound doors. At the time of Holo and Lawrence's journey, the abbey was in the charge of Elsa Schtingheim.
The abbey was founded by Father Franz three or four decades before Holo and Lawrence visited Tereo. As Tereo Church, it ostensibly brought the village under Church influence, but in reality the villagers continued to worship the local snake deity, Lord Truyeo, while greatly respecting Franz as an individual. Ironically and with Franz's knowledge, the abbey was constructed over a giant tunnel that once served as a winter den for an actual snake spirit. The tunnel has since been repurposed as the abbey's emergency escape route.
Relatively unused and isolated, the abbey was a perfect location for Franz to collect and study pagan tales without fear of reprisal from either the villagers or Church superiors. His writings were hidden in the abbey's basement in a secret room under a statue.
Although the abbey successfully concealed Franz's works, it became a target for the Enberch Church of Saint Rio shortly after Franz died. The rival church sought to discredit Tereo Church primarily for economic gain at the expense of the entire village. The attempt failed due to the bold defiance of Elsa, aided by Holo and Lawrence . As a result, Tereo Church has recently gained positive attention from its community as well as the reluctant endorsement of its rival church.