The Flood, which was once one of the two main antagonists of the Halo series as a whole, have not had much of a presence in the franchise since their defeat at the end of 2007's Halo 3. They briefly threatened to return in full during the events of Halo Wars 2's Awakening the Nightmare DLC, but Banished forces managed to stop the outbreak before it got out of control. Since then, many have wondered when — or if — the Flood will appear once again.
Warning: Spoilers for Halo Infinite's campaign follow, so proceed with caution!
A secret easter egg in Halo Infinite may hint at the answer. While the terrifying parasite didn't directly appear in the Halo Infinite campaign, players did notice that in the game's second level, Foundation, a Forerunner cylix labelled with a Flood Infection Form symbol could be found in a secret room (thanks, HiddenXperia). You can reach the room yourself by going down the hallway found on the right side of the back of the room you fight Halo Infinite's first boss, Tremonius, in.
As players discover in the campaign, these cylixes were used by the Forerunners to store specimens of each species in the galaxy so that they could reseed life throughout the stars once the Halo rings were fired to quell the threat of the Flood. It appears that as part of their plan to research the Flood to create a cure or some other type of countermeasure before resorting to using the Halo rings, the Forerunners also used these cylixes to safely contain Flood forms and make them easier to study. This is supported by the fact that in-game, the cylix is being constantly scanned by some sort of automated Forerunner machine.
Unfortunately, containment measures can be breached, which is exactly what happened in Halo: Combat Evolved when the Covenant accidently let the Flood out, and again in Halo 2 when Sesa 'Refumee, the leader of a heretic faction, intentionally released the Flood in an effort to kill the Arbiter. The Forerunner cylixes on Zeta Halo thankfully can't be opened without the touch of a human "Reclaimer," but that doesn't guarantee that an outbreak couldn't happen — for example, Halo Infinite audio logs reveal that Banished forces forced UNSC POW Lucas Browning to open the cylix that contained The Harbinger.
With the Halo Infinite ending and post-credits scene suggesting that a large conflict between the UNSC and both the Banished and the Endless is going to happen soon, the threat of contained Flood forms like this one breaking out is very real. Atriox and the Banished have witnessed how ruthless the parasite is. Will they attempt to release the Flood to weaken humanity if the UNSC manages to successfully oppose them? Could the Endless? Could damage caused by upcoming battles disable the systems keeping the Flood contained in cylixes, resulting in an outbreak?
Ultimately, there's no way to know how the Flood will be a part of the future of Halo until we know more. But it's scary to think that as the Master Chief and his UNSC allies prepare to stand against the Banished and the Endless on Zeta Halo, Flood forms housed in cylixes lie dormant beneath the ring's surface ... just waiting for someone — or something — to release them.
The Halo Infinite campaign is available now for $60 on Xbox Series X, Xbox Series S, Xbox One, and Windows PCs. It's one of the best Xbox shooters ever made, so you should definitely pick it up and give it a shot.
Master Chief's next adventure
A new Great Journey awaits
Halo Infinite's campaign has a great story, incredible gameplay, and breathtaking presentation. It's everything a Halo fan could want, and we can't recommend it enough.
I thought the Endless WAS the Flood the whole time I was playing.
The Endless are a species that somehow survived the Halos firing. The Flood are Precursor-derived parasite that caused huge problems for the galaxy twice. The first time, the Forerunners built the Halos and killed every sentient species in the galaxy, and then reseeded every planet with specimens from the Ark. The Forerunners decided to keep some Flood in captivity so that if they return from beyond the galaxy, they won't be such an unknown threat. The second time, the Flood was defeated with a localized Halo firing, but specimens remain at various Forerunner facilities.
I think Atriox knows better than to release the Flood. But there's a real possibility that damage from battles will cause the Flood to be released, or the Endless might release the Flood due to their immunity to the Halos firing.
I thought that at some point in the story flashbacks there was an offhand reference to Flood being on the ring but then they allude to "something worse" which ended up being the Endless. But my housemates don't remember that cutscene so maybe I imagined it.
No that cutscene is in the game, and it indeed implies the Endless are worse than the Flood. But the Flood are here too, which is scary lol.
I particularly want to see what they can do with some more unique flood variants, like brutes or even just the fauna roaming around the ring. They could also provide more variety between elite and human flood variants.