What is the Forerunner Keystone in the new Halo show?

A strange artifact is taking center stage in the new Halo TV show. Just what is the Forerunner Keystone, and what role will it play in the plot?

In the first episode of the new Halo show, Master Chief’s Silver Team thwarted a Covenant attack on a rebel outpost in Madrigal and stole the item the excavation team was sent to extract. The mysterious artifact brings back Master Chief’s memories of his life before the Spartan-II program, and is a huge priority to both the Prophets and Makee. So what is the Forerunner Keystone and what role will it play in the new Halo show?

What is the Forerunner Keystone in Halo?

The artifact retrieved by Silver Team on Madrigal is a Forerunner Keystone, a device holding information on the galaxy-razing superweapons known as the Halo rings. The Forerunners were an ancient race of aliens who left their star-spanning empire for humanity to reclaim, judging them as the next worthy species to shepherd the galaxy. Keystones offer access to eons of Forerunner information and seems to hold the location of the titular Halo rings.

Master Chief’s first interaction with the artifact returns some of his memories of his life as a child before being kidnapped by ONI and turned into a walking weapon. At the same time, the Covenant Prophets appear to have taken a young human girl into their care who they think is a Blessed One, a term they also use for the Master Chief after a Sangheili elite witnesses him interface with the artifact. Certain humans seem to be capable of interfacing with these ancient relics more readily than others, and are dubbed “Blessed Ones” by the prophets.

These keystones seem to be the key to humanity and the Covenant finding the Forerunner’s deadliest secret. The Halos are a series of ringed weapons systems spread throughout the galaxy that can wipe out all organic life in a last-ditch effort to stop an alien parasite known as the Flood. The rings are referenced in association with the artifacts by both a human in The Rubble and the Sangheili elite who saw Master Chief interact with the key.

Halo TV Show theories – post EP1

This keystone is clearly meant to be the central Maguffin for Master Chief and the aliens to chase until they stumble across a ring itself in the new Halo show.