>>534936335
>Before 4 he was just a player insert with no real personality.
Lore-accurate.
Spartans come in different generations, and his generation was the "abduct children, pump them full of whatever the fuck kinda bio-engineering shit we have lying around, and doctrine-train them into absolute killing machines"

Chief has no personality because he doesn't need to. He got raised to shoot bad guys and afraid of no evil. Now he's growing old and grumpy, cause he's been there for the whole ride.