Is the hero in Metal Gear Solid called Naked Snake or Solid Snake

Technically both, even though they are different people. Naked Snake was the main character in Snake Eater (which took place in 1964). Solid Snake is the main character in most of the others, and he was born in 1972. Naked Snake later became Big Boss. Solid, Liquid, and Solidus Snake were all cloned off of him in the Les Enfante Terribles (Terrible Children) Project. Solid Snake is the main character and hero in the series, though. Big Boss was the main character in a few of them to give backstory.