The Covenant: Starting from the bottom

The Unggoy, known commonly as the grunt is, in my opinion a really adorable enemy in halo 2 but after that they got ugly and i enjoyed killing them in droves. The reason we see so many grunts in the games is because they can breed at a fairly fast rate. The covenant leader's use this to their advantage to beat their enemies by sending an overwhelming amount of these creature's to fight their enemies. People percieve these guy's to be little, i had thought they were maybe 3 or 4 feet tall upon encountering them but their average height is around 5ft. it's probably because john-117 is almost 7 ft tall. They also breath methane, that's why they're always wearing those spikey suits and masks. This is likely the reason their blood is blue. Well these guys had a history, before the forerunner's hit the reset button for everybody the grunts got to the industrial age, not really impressive but they let it get so filled with pollution it destroyed their planet, even less impressive. They could barley survive on their planet even after the forerunner's reseeding (that reset button) so joining the covenant, which wasn't optional, was probably the best thing to happen to the little guys. They got mistreated and were pretty much slaves until they rebelled. They lost to the covenant and got pretty much destroyed for it but they weren't about to kill them all, they gave them a slightly more important role and they became infantry instead of just meat shields. They are smarter than the covenant give them credit for, they can absorb knowledge and have an understanding of the human languages. I think that if the humans could have convinced them they were a better ally, even just a few of them, they could have bred an army that would have been invaluable to them. read more at http://halo.wikia.com/wiki/Unggoy

the blue blood

grunts over the years

Precursors, true winners

These guys are the best of the best. There isn't much history about them, they were all practically killed off by the Forerunners. They made the Forerunners and Humanity, they were so advanced they could accelerate the evolution of species. Similar to the de-evolving that the Forerunners did to ancient Humanity. The Precursors were somewhat near gods, they were so ballin they thought nothing would defeat them. They could build bridges between planets and their technology was based on neural physics which says that everything in the universe is alive but beyond our comprehension. This meant that the Precursor structures were indestructible by most means except for by the halo arrays. The Precursor's became the flood, originally the powder found by humanity I mentioned was supposed to be used to resurrect them but over the years it became corrupted as the Precursors went insane. They say that the only reason the Precursors lost to the Forerunners is because they thought that their creation wouldn't rebel against them, this idea was way to outlandish for them. Their creation betrayed them so their next creation was to know only suffering so it would never go against them. If the flood was for revenge against the Forerunners they succeded because they got recked too. The later generations of Forerunners actually didn't know that their race did this to the Precursors and they were probably really suprised when they came back with the whippin stick.
http://halo.wikia.com/wiki/Precursor <- what little more there is to know

The gravemind claimed to be the last precursor. 

Forerunner Tech

They made halo which is probably the pinnacle of weaponry. A halo is an amazing creation, there is a teleportation grid throughout the whole ring. It can support life, in the books it talks about forerunners being able to create planets.They could even create suns. Hard light was another one of their notable achievements, as seen in the games, they are the bridges that appear out of thin air. Hard light and eventually plasma is used in their infantry weaponry. The monitors used to guard and take care of halos were also extremely powerful, their beam weaponry is stronger than most. The sentinel is a fantastic machine. If it operated in the games as it did in the books there would have been no way to win. They can combine with other sentinels and turn into a super weapon of its own, able to destroy the covenant's ships with ease. Their power armor, called combat skins, was the top of the line. It increased their longevity and made them immune to disease, could even feed them, all of them had artificial intelligence, and allowed them to connect to the domain. The domain is like our internet, it had the sum of their knowledge. the events in Halo: Combat Evolved take place 100,000 years after all of the forerunners died off so their technology remained intact throughout the galaxy. Their buildings are said to be reinforced on a molecular level making them nearly impossible to destroy. They were able to easily travel through slip space and even built worlds in it, which is basically a place outside of everything we can percieve. The shield world they built was like another world within a world. Too bad they never made it there, those darn A.I. can't be trusted. However, their technology wasn't the most advanced. They were a tier 1 civilazation while the precursors were a tier 0 civilization. ( http://halo.wikia.com/wiki/Technological_Achievement_Tiers)

This feller (mendicant bias) made the Forerunner's lose against the flood. Monitor shaming :p

Sidetrack: The greatest gun ever. hands down.

If you're thinking anything besides the scarab gun from halo 2, you're wrong and you lose. Now look at the title, you might be thinking oh well halo can kill everyone instantly but I said gun foo! This weapon is so potent, so powerful, it distorts the screen when you fire it. Aside from the fact that it has infinite ammo and you never have to reload, it's in the vanilla game! no mods necessary. This gun spits out a giant beam of death. I've tested to see how far the beam goes and we sat at opposite ends of the level and i still hit him smack dab, insta-kill. The enemies on legendary cower in fear from the unholy wrath of John and his scarab gun. Also found in the level, relatively nearby, is a giant soccerball. My friend and I turned it into the new sputnik with the scarab gun, he flew to the very top of the map and the fall was hilarious. Crushed against the sky by a giant soccer ball, what a way to go. This weapon is of the finest quality and i hope that anyone who has played Halo 2 has gotten it atleast once. They shoulda had it hidden somewhere in all of the games in my opinion. Read all about it here; http://halo.wikia.com/wiki/Scarab_Gun

Flood Origins

So the Forerunners killed off and banished the surviving Precursors, bad move on their part but they don't know it yet. They did it cuz they're greedy and wanted the mantle of responsibility that the humans were originally going to get. The mantle of responsibility says they will try to preserve all life. But some odd years later ancient humans found a space pod, of sorts, filled with powder. The ancient humans were like lets see what this stuff does and gave it to an animal, called Pheru. This animal was a delicacy and eating it meant you were successful or something of the sorts. The powder made them grow at faster rate and they were eating it and thought everything was going just fine. Well one day their favorite little animals started growing tentacles and other mutations and then they started thinking something might be wrong. Well they were totally right, the flood came as the scourge of many human controlled planets. The flood are essentially super-zombies, The Walking Dead zombies have nothing on these guys.  The flood opened up a life time supply of cans whoop-a$$ until the humans found a cure for it. At the same time they were expanding into Forerunner controlled space but that war is for the next post. Read about it with better detail (and less love) here: http://halo.wikia.com/wiki/Flood

Pheru ^

Forerunner love, Blog intro

I'm pretty biased in thinking the Forerunners are the most BA race in the Halo universe. They developed a weapon that literally kills everyone. Unfortunately their advanced artificial inteligence was convinced by a precursor, another very advanced race ill go into detail later, to blow them all to smitherenes. I guess that's the ultimate revenge from the precursors for their defeat by the forerunners. It doesn't stop there though! The Precursors also made the flood which is pretty much the scourge of all existence. The flood actually comes from the precursors, like a descendant, but came in the form of powder used by ancient humanity to grow an animal which was a delicacy to them. As much as I love the Forerunner's for their advanceded-ness and how they have 999 attack, ancient humanity was probably the superior group. They fought off the flood and the Forerunner's at the same time, they even found a way to completely defeat the flood, by making a reverse flood, talk about creativity! How to beat zombies? make a zombie virus that turns the zombies back to normal and infects the others all the same ^_^ Too bad the forerunner's had to pick a fight with our ancient ancestors and they destroyed that cure, causing the Forerunner's to make halo. All of these event's i'll go into greater detail but for everything in greater detail go to: http://halo.wikia.com/wiki/Main_Page. Gravemind (flood leader) 1st row left. Forerunner 1st row right, ancient humanity below Forerunner. Precursor below ancient humanity.