|Location||The Ark & Dove Cathedral|
The Tribals are a cult found in Fallout 3's fourth DLC pack; Point Lookout. They are known as a peaceful tribe, but their leader Jackson met Professor Calvert and believed he was some kind of god and followed his every order, including the attack on the Calvert Mansion.
Their main base is The Ark & Dove Cathedral, but you'll need to complete the Walking with Spirits quest before you can enter. The quest involves traveling to the Sacred Bog and taking Punga Seeds from the Mother Punga. Removing the seeds will result in hallucinations, during this time, Tobar will enter the bog and remove a small part of your brain. Those who survive and make it back to the Cathedral will be accepted into the tribe.