Halo Season 2: Onyx, Explained

Halo Season 2, Episode 6 shifts the Paramount+ show’s action to the planet Onyx. With this in mind, we’ve explained everything you need to know about Onyx – both in Halo Season 2 and the original video games’ canon – below.

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What’s the Deal With Onyx in Halo Season 2?

Onyx is an artificial planet in the Halo universe’s Zeta Doradus system. It’s the location of the Office of Naval Intelligence’s (ONI) secret headquarters. As such, much of Onyx’s history is shrouded in mystery, although franchise protagonist John-117/The Master Chief and ex-Spartan Soren-006 identify Onyx as the home of the Spartan-II program they endured as children.

Onyx’s Spartan-making days aren’t behind it, either. While surveying the ONI base in Halo Season 2, Episode 6, “Onyx,” the Master Chief and Soren correctly deduce that the next generation of Spartans is training there. We get insights into this training throughout “Onyx,” notably the Spartan-III recruits’ heavy use of VR simulations as part of their combat prep. ONI’s Onyx facility also has a war room, advanced labs, and holding cells capable of detaining a Spartan (the Master Chief still escapes, though!).

Aside from the ONI base up top, Onyx also boasts a labyrinthine network of caves down below. These underground caverns house a sprawling Forerunner megastructure, which – assuming the Halo series version of Onyx mirrors that of the games – represents the “real” Onyx, not its natural-looking outer crust. The full extent of the Forerunner complex’s capabilities remains unclear in Halo Season 2, however, an ONI research team led by Miranda Keyes is seemingly on the verge of figuring this out.

Related: Halo Season 2: Who Is The Mother, Explained

What Do We Know About Onyx From the Halo Video Games?

The broad strokes of the above also apply to the Halo video games’ conception of Onyx – with a few notable exceptions. For starters, only the Spartan-III program has its roots on Onyx in the games and tie-in media. What’s more, ONI’s base on the faux-planet, Camp Currahee, doesn’t double as the intelligence outfit’s headquarters (although it is a top-secret installation all the same).

All that said, Onyx’s defining trait – its natural exterior/artificial interior – is (as mentioned before) very much a part of the Halo games, too. Indeed, fans up-to-speed on OG Halo lore already know the purpose of Onyx’s Forerunner core: housing a shield world. This is a cosmic safe space for sitting out the devasting effects of the Halo Array, and is protected by the countless Onyx Sentinels that collectively make up most of Onyx’s actual mass.

Halo Season 2 is currently streaming on Paramount+, with new episodes dropping Thursdays.