One of the biggest mysteries in Halo Infinite is who the Endless are and what happened to cause them to be imprisoned on Zeta Halo. The Harbinger, a foe that is working with the Banished, is trying to revive the Endless. Obviously, if the Endless are released, bad things will happen, but why?
Who are the Endless in Halo Infinite?
Unfortunately, we don’t get a real answer to the question of who the Endless are in Halo Infinite. Just before the fight with the Harbinger at the end of the game, they state, “We stood. Silent. Unable to speak as they passed judgment,” and “Our return is their reckoning… and it is yours as well, Reclaimer!” This phrasing seems to indicate that they are an Endless. However, they reveal very little about their history, so it’s hard to verify their claims.
All we know about the Endless is that Cortana and Zeta Halo’s monitor considered them to be “worse than the flood.” We also know from the Legendary post-credits scene that the Endless are unaffected by the firing of the Halo array. It could be that the Forerunners imprisoned the Endless due to their immunity to Halo, but the tone we get throughout the story implies something much more sinister than that.
At the end of the game, we access the Silent Auditorium, and it’s explained to be a courtroom, prison, and place of execution rolled into one. According to the Harbinger, the Endless were tried here, and that the Forerunners passed Judgment on them.
With the info we have, we can make some speculations. Despite obviously having execution facilities, the Forerunners contained the Endless deep inside of Zeta Halo instead of killing them. Perhaps this is because “Endless” is a reference to their immortality and not their numbers. The one race we know to have a potentially infinite lifespan is the Precursors, the source of the Flood and sentient life in the Milky Way Galaxy. It’s possible that some of the survivors of the Forerunner’s betrayal were locked away so that their secrets could be studied.