The early Spartans were children with a specific genes or some such. they were abducted and trained in secret their whole lives.

It was time consuming and very costly to make them.

How do the Spartan 3 and Spartan 4 differ from the Spartan 2?

Master chief is only a NCO but the later Spartans have commisioned ranks.

2 Answers 2


Spartan-IIs were children, abducted at a young age and taken to Reach, where they were forcibly put through the program. IIs were heavily augmented to the point where many died and a number of others were permanently crippled. It is noted that, advanced armour aside, a Spartan-II was by far the most capable and most dangerous of all the Spartan generations. John-117 is the most well known of the second generation.

After the success stories of the Spartan-IIs started coming in, it was decided that Spartans were a good idea, but there were problems that needed to be addressed:

  • There were simply too few Spartans due to the very specific genetic sequences required for selection
  • The augmentation process was too harsh on the childrens' bodies, resulting in a ridiculously high mortality rate during training.
  • The cost to build and train even one Spartan was far too costly, especially with funding being diverted to the Mjolnir armour program.

For these reasons, the process for creating Spartans was heavily changed once work on the third generation commenced. The selection process was expanded to accept children with more diverse genetic material, allowing hundreds to be trained at a time, and the augmentation process was relaxed so as to ensure a maximum survival rate at a much lower cost, though at the cost of diminished capabilities compared to the Spartan-IIs. Noble Six is the most well known and arguably the most capable of the Spartan-IIIs.

So the Spartan-IIIs were cheaper, less capable, and more expendable than Spartan-IIs, but they were still fundamentally super soldiers. They didn't show quite the same level of success as the IIs, with some missions resulting in the deaths of every Spartan-III that was deployed, but the missions were still seen as victories, so a 4th generation of Spartans was approved.

Spartan-IVs were drastically different to their predecessors. For starters, every Spartan had to be a consenting adult volunteer, meaning no more abducted children and no more forced augmentations. The selection and augmentation process was also changed to have no genetic requirements and a maximum survival rate. This meant that any of the volunteers would have an almost perfect chance of successfully becoming a Spartan, but despite advances in technology, this also meant that their abilities compared to a Spartan-II were greatly lacking. This was not seen as a problem, however, as it has been noted that a Spartan-IV in modern Mjolnir armour could hold their own against and even defeat a Spartan-II wearing the Mjolnir armour of their time. If all equipment is equal, the Spartan-IV would have no chance.

BONUS: There was also developed in secret an experimental set of Spartans between the third and fourth generations. These Spartans were augmented and trained so heavily that it was thought they would render Mjolnir armour obsolete. Unfortunately, only one of the participants, Ilsa Zane, survived, and it cost her sanity to do so.

Essentially, the difference between Spartan generations is the way they've been augmented and trained, with each subsequent generation being less capable and more reliant on their armour upgrades than the last.


The Spartan IIs were made to use MJOLNIR, which normal people couldn't use without breaking their bones. There was an Orion or spartan I project, but it was done on adults and was mostly a failure, though Sergeant Johnson and Forge were both participants. The Spartan IIs were trained for 6 years with an extra year after augmentation, and were pushed to the limits of human ability but were intended to be capable of being Officers, and taught education as well as tactics. The Spartan IIIs augmentations were the same, but safer, essentially a quantum leap in the technology. They also had their brains modified so that they could tap into the animal parts of their brain when injured, this increased survivability but required meds to avoid them losing higher cognitive function. The Spartan IIIs received training from some Spartan IIs and other spartans in the field, while the first generation received only the first 6 years without an extra after augmentation, all survived augmentation. CAT II Spartan IIIs are considered the best, they received the best training for 8 years from qualified Spartans and were the most motivated, some were considered geniuses, they also matched the original gene requirements, these were likely the best Spartans. However, most Spartan IIIs were given cheaper armour that didn't boost strength or reflexes, and sent on suicide missions, with only the best of the best being given MJOLNIR. Spartan IVs, were the weakest in terms of augmentation, but were given the most advanced armour. Note that while their armour allowed them to fight at similar levels to Spartan IIs, it relies on computers, and they can't use it to it's fullest potential. It also has less armour than previous generations, and is reliant on superior shielding. However the UNSC managed to make it cheaper, and as such the Spartan IVs far outnumber the previous Spartans since any soldier can qualify for the augmentations. There was a comic where the UNSC attempted to Spartans that didn't need armour, but it resulted in high instability with only one survivor, who went on to join the resurrection, she was able to match Spartan IVs in combat without the benefit of the force and reflex enhancing armour, but her skin couldn't survive the force of her punches.

Essentially Orion resulted in people at the absolute limit of human ability, Spartan IIs resulted in genuine Superhumans, smarter, faster, stronger than any other soldier with the best equipment available, Spartan IIIs were trained for suicide missions but were trained harder and given an augmentation that made them akin to Berserkers on the battlefield to make up for their cheaper armour. Spartan IVs are essentially Orion 2, not spartans at all outside the suits, but inside they are capable of matching what the previous generations could do to an extent, and they are the most numerous, numbering in the thousands. It's likely even corporate entities can hire Spartan IVs. That said, they were made by 343 around the time Eric Nylund left, a lot of fans as such don't like them, or don't consider them canon. There was a big tone shift around then, that basically made Halsey out to be space Hitler, rather a genius scientist who wanted to advance human evolution.

  • 1
    Whilst a nice and detailed answer it would be improved by editing in supporting evidence where possible.
    – TheLethalCarrot
    Aug 11, 2019 at 15:21
  • More than evidence, some of this stuff is actually incorrect, only Gamma Group of SIIIs got the 'berserker' augmentation, and Orion was by no means a failure, with it's soldiers being the best of the best, it's only failure was the massive washouts in augmentation. I also didn't explain SPI armour, which had two forms of active camouflage technology depending on which variant, had a VISR that was able to detect 'cloaked' Covenant forces, which we haven't seen MJOLNIR replicate. Sep 14, 2019 at 13:38

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