A new teaser trailer for Paramount's live-action Halo series has been released, and its reveal of High Charity creates some question marks about which game the show will be adapting (the first Halo game or Halo 2). Serving as the large mobile station of the alien Covenant forces, High Charity wouldn't make its first appearance until after Halo: Combat Evolved, the first game in the Halo franchise. As such, does this mean that the upcoming live-action series will begin with Halo 2? Not necessarily.
In the first Halo game, the UNSC's Master Chief Petty Officer John-117 successfully repelled the united alien forces known as the Covenant, the sworn enemies of humanity. With both sides battling on the newly discovered planetary ring known as a "Halo", Master Chief destroyed the first Halo ring seen in the series along with several Covenant forces in his efforts to prevent the ring from eradicating all life within 25,000 lightyears. However, the Covenant's united mobile homeworld known as High Charity wouldn't arrive until after the events of the first Halo game.
High Charity's first appearance in Halo was in First Strike, a novel that served as a prequel to Halo 2 (the station's first in-game appearance). Resembling a giant artificial mushroom that housed the Prophets' Holy City where the Covenant's hierarchy ruled, the shot of High Charity in the Halo first-look trailer is unmistakable. However, this doesn't inherently mean that the Halo live-action series will begin with the events of Halo 2. Instead, it seems more likely that the show will reveal High Charity as a means to provide a greater introduction to the Covenant forces before they engage in battle with humanity for the first Halo ring.
It would certainly be odd for Halo to gloss over the origin story of Combat Evolved and dive straight into Halo 2's narrative. There are simply too many major concepts, characters, and factions introduced for an exposition dump to handle. Instead, viewers should expect Paramount's Halo to feature some minor changes and tweaks to the first Halo plot as a means to make it more cohesive for the new live-action medium (like High Charity getting an earlier introduction).
Seeing High Charity before the events of Halo 2 likely won't break the overall franchise story in any way. The odds are good that the Covenant's united homeworld will simply be featured as a means to show where the alien forces came from before they fight Master Cheif and the UNSC in the events of the first Halo game. While High Charity does have a greater role in Halo 2 and beyond, it will likely be saved for possible future seasons of the new Halo series down the line.
Halo will begin streaming in 2022 on Paramount Plus.