The question of just how inspired Bungie was by Larry Niven's Ringworld series has been quietly boiling in the background and bubbles up every time a new Halo comes around. Of course, burden for this comes down to Bungie as they were the original team to put the Halo IP together. Bungie themselves have commented on the similarity of the game and Niven's novels, and have since the original game was first announced. However, with Halo 6 rumored to be in development with a reveal coming (likely at E3 in just a few months time) it's good to look back at the similarities between the novels and the game series, if for no other reason than some cultural background.
In an online exclusive interview with Next Generation (archived on Marathon's Story's Halo page) one of Halo's early developers gave the following statement:
We wanted to make the definitive game of conflict between the human race and an alien civilization. There have been countless games on this theme, but few of them have the depth of story, detail or originality that you would find in a good sci-fi novel. We're going to write this story, and bring it to life with the best technology available in an electronic game.
One of the things that was most rewarding about the Marathon series was the way that fans pored over the details of the story, analyzing and debating it, and eventually expanding it beyond what we originally had written. Two years after we shipped the third in the series, Marathon Infinity, we could still check out third-party sites to find out the new developments there were in the Marathon world — it was a blast. That taught us that a complex story reaps benefits long after players have played through the game, and that's very much our intention with Halo.
It's worth noting that though Halo takes place on a ring-shaped artificial world, the story, characters and world bear no relation whatsoever to Niven's excellent Ringworld novels.
And that's pretty much been the party line ever since. However, dedicated fans don't quite agree. After all, there are some eerie similarities between the Halo and Ringworld series like the inclusion of a map room or the fact that both are centered around ring-like objects in space that can house their own ecosystems. But then again, map rooms and ring-like colony objects aren't exactly specific to Ringworld and Halo alone either.
Still, we can at least look at the similarities between the Halo and Known Space universes and draw our own conclusions.
Beyond the obvious similarity of habitable large scale ring-shaped structures, there is also the backstory conflict between the Forerunners and the Flood, which is similar in flavor and resolution to the Slaver-tnuctipun conflict in Niven's Known Space universe.
- The Flood parasitized sentient life. The tnuctipun were master geneticists who created life forms that were presented to the Slavers as gifts which later turned out to be weapons.
- The Forerunners developed the Halo array to wipe out all sentient life in the galaxy. This would deprive the Flood parasites of new hosts and wipe them out. The Forerunners activated the weapon and vanished. Plagued by the tnuctipun bioweapons, some of which were intelligent species in their own right, the Slavers had a slave race create an amplifier for their psi-talent. The Slavers then broadcast a suicide command to the whole galaxy. Everything intelligent enough to understand the command obeyed and died, including the Slavers themselves.
- In both universes this galaxy-wide extinction event wiped the slate clean, giving time and space for sentient life to evolve again over billions of years. Eventually these new beings would become spacefaring and begin to stumble over the abandoned ancient and deadly technologies of the old conflict. In the Halo universe, humans find the old Halo weapons and inadvertently unleash the Flood. In Known Space, humans and other species seek out Slaver stasis boxes and unleash many dangerous things, including dormant Slavers, tnuctipun, and the Slavers' suicide weapon.
The backstories are similar in broad strokes, but the Halo gameplay diverges wildly from anything depicted into Known Space literature. I think there is enough here to suggest Known Space influence in the setup of the Halo saga, but nothing beyond that.
There is no damning evidence or smoking gun of theft here. And while Halo 6 isn't yet official, I think we can finally put this one to bed. Yes, both are similar tales involving ring-like space structures, but that's about where the similarities end.