I don’t know how he get so tall but i was wondering will he be the same height in halo 5?
You should read some of the novels. I enjoyed reading them and I normally don’t like fiction. I’ll put the ones having to do with MC in order for you.
Fall of Reach - The Flood - First Strike
This has a lot of back story to the Spartan II’s and the Halo universe as a whole. It also explains why Sgt (then later Sgt Maj) Johnson survived the first halo ring.
If you don’t want to do a lot of reading look here:
If that’s too much, basically the augmentations that the Spartan II’s went through made them “smarter, better, faster, stronger.” They also made them really tall.