Metal Gear 1

SPOILERS! In Metal Gear 1 the final boss is not Big Bos, but it is Venom Snake. This is known because at the end of The Phantom Pain Venom Snake has this cassette tape named the man who sold the world, from the real Big Boss. Venom Snake finds out that he is not the real Big Boss but he continues to hold the title of it because Big Boss insists he does. Then Venom Snake flips over the cassette tape and it reads, "Operation Indrude N1N3"  So Solid Snake kills Venom Snake not Big Boss.