8. Ocelot & Big Boss
Although they were enemies for most of Metal Gear Solid 3, Revolver Ocelot and Naked Snake - who would go on to become Big Boss - eventually learned to respect one another in the wake of the events of operation Snake Eater. The two would eventually end up being founding members of the Patriots, with Ocelot only agreeing to become part of the unit if Big Boss also did. The two seem to therefore have an unexplored friendship throughout the years after Peace Walker and up to the Phantom Pain. The bond between the two is strong already - Ocelot is actually the son of the Boss, while Big Boss was trained by the Boss. The two understand her will to unite the world under one banner and use this as a founding mantra of the Patriots, but dissolution between the group due to misinterpretation of the Boss' will eventually leads to Big Boss leaving, Les Enfants Terribles and Ocelot continuing to resentfully do work for the Patriots. Ocelot would then eventually go on to try and stop the Patriots in MGS4, but his descent into villainy, and his mostly unexplored relationship with Big Boss, remains a series mystery that I'd love to see resolved. Are you still following? I'm starting to confuse myself.