In mgs4 its snake,he aged quickly because he is a clone and also because he is injected with the fox die virus. Big boss is dead and will remain the same way until mgs4 shows else. Why did bigboss defect? Well if u played snakeeater u will know that the whole mission of the boss betraying the US ,bigboss having to kill her was all set up by the US to get the philosophers legacy. Bigboss never knew that so he felt betrayed.even in po the patriots use snake for their own needs,ocelot kills the patriots and he along with bigboss become the new member of the patriots along with the 3 member who is not yet disclosed(the man who planed the whole events of mgs3 and mgs po)
We're not tools of the government, or anyone else. Fighting was the only thing... the only thing I was good at. But... at least I always fought for what I believed in.
hideo's brief to shinkawa while designing otacon was an overweight burger and fries munching nerd. shinkawa chnged the design without informing hideo ,but when he showed it to hideo he liked it and was new design was retained.