The Taken would win. I love Halo, and the Flood are a fantastic and interesting enemy faction. But the biggest difference between them and the Taken is that the Taken don't even have proper biological forms anymore. To quote the Desolate Gauntlets: [i]More than shadows, but less than starstuff.[/i] And when you kill a standard Taken enemy, excluding Ultras, their bodies are swallowed up, as if Oryx is re-Taking their essence. When you look at their death animation, you can actually see the Dark star that Oryx uses to Take them. Now then. The Flood and the Taken both need a steady supply of bodies for reinforcements. However, the Flood are incapable of properly infecting a Taken because again, no biology. No nervous system for an Infection Form to tap into. Oryx simply needs a living being to Take them, and all the Flood are living. With conversion aside for a bit, let's talk arsenal. The Flood use the same weapons as their infected host, at least until they hit the Organized stage and have enough biomass to create Pure forms. The Taken do as well, but always with a twist. A Vandal-turned-Combat form would still be using an Arc Wire Rifle, and would be faster and probably more resilient. A Taken Vandal uses a Solar Wire Rifle, and the Flood have been proven susceptible to fire, and a Taken Vandal can also pop the <this is my space> bubble to heal. A Flood Thrall, considering how Thralls already might as well be skin and bones, would likely be turned into a Carrier Form. A Taken Thrall is stronger, has Solar-charged claws (again, Flood are susceptible), and can [i]teleport.[/i] So in a 1 on 1, the Taken Thrall would go <sideways> to the Carrier, slash it, then go <sideways> again. This is the same attack pattern used in-game. A Taken Acolyte essentially creates an autosentry from Halo 4, but stronger, more health, and a faster fire rate. The autosentries in 4 were designed to combat the Flood. The next issue is mobility. [url=https://www.halowaypoint.com/en-us/universe/vehicles/indulgence-of-conviction]Yes, the Flood can take over entire ships[/url], but the Taken reside in the Dreadnaught... And are able to warp en masse to anywhere in the solar system that the Dreadnaught is currently located in. And that's according to what we see in-game. So, you have an enemy that can take over ships, versus an enemy that doesn't need them to get from place to place. The biggest problem is that we're comparing Halo and Destiny, and Oryx in Destiny is AT LEAST as powerful as the Warp Gods in Warhammer 40K. The only reason Guardians were able to kill Oryx both times in the first place is because he wasn't actively planning it all. He was pissed that his son was killed, and wasn't thinking rationally. Meanwhile in Halo, yes you have the Forerunners, and the Flood which are the remains of the Precursors after the Forerunners rose against them (note that the Precursors built structures out of thought itself, according to the Forerunner trilogy. A test-firing of an early Halo destroyed a massive star road built by the Precursors, showing that it was indeed constructed from neural pathways), but they still don't hold a candle to the God of Understanding.