3. Liquid Possessing Ocelot
KonamiIn the original Metal Gear Solid, Snake has a whole series of enemies but only two could really be referred to as nemeses. Revolver Ocelot is the first one that you'll encounter and his love for revolvers, dusters and spurs made him an instantly recognisable character. The other is Liquid Snake, Solid Snake's clone brother, and he serves as the game's primary antagonist. He's defeated at the end of the game though, making his rivalry with Solid brief but intense... Or so you might think. Kojima saw the popularity of Liquid and decided to bring the character back in appropriately ridiculous circumstances. Revolver Ocelot lost his right hand during his fight with Snake (Grey Fox cuts it off) and between the first and second games in the series, he replaces his entire right arm with that of the now deceased Liquid Snake. This had an unintended side-effect though (or did Ocelot intend to unite with Liquid?) as Liquid Snake possesses Ocelot's body, combining the two entities to become Liquid Ocelot. The character plays a semi-big role in Metal Gear Solid 2 but it's in Metal Gear Solid 4 where he fully unleashes his plans for world domination. Guns Of The Patriots also gives a reason behind Ocelot's apparent possession too; of course, it all comes down to nanomachines which apparently transplanted Liquid's psyche into Ocelot, rather than an actual possession. Still, acquiring one man's arm so you can combine your evil powers and go and conquer the world is a pretty ridiculous concept, but hey, it leads to a pretty intense final showdown.