Flood vs Covenant Covenant. Wider range of weaponry and infantry. As far as I know, the Fallen have no heavy ordnance for their ground forces whereas the Covenant have counters and then some to all Fallen tech. Fallen have the Shock Pistol, while the Covenant have the Plasma Pistol. Relatively equal, but the advantage goes to the Plasma Pistol due to overcharge. Fallen have Shock Rifle, Covenant have the Needler. Advantage Needler: both have target tracking but Neelder is higher fire rate and sounds detonate. Fallen have the Shrapnel Launcher, Covenant have Plasma Rifles, Concussion Rifles, and Plasma Carbines. Advantage goes to Covenant due to versatility. The only equal ground for infantry weaponry is with the Wire Rifle vs the Beam Rifle. The Scorch Cannon could out perform against the Covenant Fuel Rod Cannon as it can be placed as a deadly trap and does not need to be reloaded. As for heavy armor and ordnance, all hands go to the Covenant (except for flagships since we can not accurately judge the combat capabilities of the Fallen Ketch ships). The wraith tank is more maneuverable than the Fallen Walker and has a more efficient fire rate. Sure the Fallen Walker has shock mines and a pulse wave to deter close quarter fighters but the Wraith can ram targets and can boost to evade. Both have similar armor (based on ground fighting with no heavy weapons or boarding). Fallen Skiffs have higher offensive output than a Covenant Phantom but the cannons are larger and easier to destroy. That makes both equal, in my personal opinion. Fallen pikes and heavy pikes are countered by both the Ghost and Revenant. Ghost and Revenant are more maneuverable and do not lose fire power with sustained firing. I would include an advantage for Jackal shields, but since Fallen use energy based weapons that is pointless. Hive vs Flood. This one is tricky. At a first glance, the advantage would have to go to the Flood. A parasitic being that consumes its host and uses it to spread, causing death and chaos. However, the Hive are sort of like a parasite in their own right. They feed off the Light and life of other beings to make themselves more powerful. We cannot compare weaponry as the Flood have none of their own other than their ability to spread. However, we could include the Taken in with the Hive as they are created by Oryx, the Hive god-king. An argument could be made that Oryx could just take the Flood, but that would not work. You could say that it is because the Flood is dead and Oryx cannot "Take" the dead, but the Flood are more like a parasitic fungus operating under a single hive mind, not dead but plant based in nature. My understanding of "Taking" is that it has to be a sentient being with its own will. If this is true, the only Flood Oryx could take would be the Gravemind, the center of the hive mind, assuming they are not immune to being "Taken" due to being a fungus. As for the Flood infecting the Hive, this might not work either depending on what level of Hive is being targeted. Thralls and Acolytes would be vulnerable, but any other Hive may be resistant to infection due to the presence of the Worm. The possessive nature of the Worm could theoretically hold back the infection of the Flood. Ultimately, I would have to give an advantage to the Flood. This is due to shear numbers. The Flood far outnumber any living being due to their ability to spread through infection. Even if the Hive cannot be infected, other races can leading to constantly growing numbers. Vex vs Prometheans This one is relatively easy to judge. Regardless of the vast amount of armaments available to the Prometheans, the Vex have a great advantage in their ability to manipulate time. As long as this power remains a secret, the Vex cannot be stopped. The only way for this to be countered is for the Prometheans to locate the Vault of Glass. This is the weakness of both sides. The Prometheans are tied to the time stream and are vulnerable to any changes made, but on the other hand the Vex rely on their tie to the Vault. Ultimately the advantage goes to the Prometheans. The Vex may be able to erase the Prometheans but that would only be in individual time streams. If in any one of the time streams that the Prometheans are not wiped out they find the Vault of Glass, they would be able to destroy it, converging all time streams created by the Vex. Now on equal ground, the Prometheans would overpower the Vex in no time. Cabal vs Brutes No comparison needed. The Brutes relied on Covenant technology. The Cabal are intergalactic destroyers. The Cabal would bombard the Brutes from high orbit, possibly destroying the planet in the process. Even if the Brutes had the Covenant backing them up, the Cabal would still win, partly due to their tenacity and willingness to do anything to achieve victory. The Cabal crashed into a system destroying Dreadnaught in an attempt to gain a foothold and held their ground. Take into consideration that we have not even seen the full force of the Cabal empire, while we have seen the full force of the Covenant.