After the Reaver cult was mostly destroyed by both the Brotherhood and the Calculator's robots, and most of its remains joined the Brotherhood, this new bunker became the last frontier for the Brotherhood. From here, the final missions against the Calculator were commanded by General Dekker.
The bunker's recruit master is Personnel Yeoman, the medical officer is Hyland, and the quartermaster is Folleto. The Auditor General could be seen here as well, along with Tiduk, who is standing near his sister's grave. The mechanic near the entrance is Allen. Like Bunker Delta, Bunker Epsilon is not an underground facility, but appears to be a hastily made base for waging the war against the Calculator.