Endless Battle Fathom is a location in Torment: Tides of Numenera.
Endless Battle Fathom
There is 3 fights waiting for you, but you dont need to kill everyone there. Some Castoffs can be persuade to leave (Persuasion skill or Tidal Surge), some may even join you (Andronous, Raima Cyro, etc.) Alternatively, you may try to turn on the 3 humming machines to weaken your enemies.
There is a Crystal near the entrance, it require 3 Might tasks to crack.