Lets first start off with the iconic characters from the MGS Saga :
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Revolver Ocelot :
Revolver Ocelot also known as Adam, Revolver Ocelot origins goes back in MGS3 he is son of the legendery solider The Boss, When Snake first encounterd him in MGS3 Ocelot wanted to do a duel with him so he can kill him just by himself but snake won that dual and after that duel ocelot started to respect Snake (also known as Big Boss) * and maybe fell in love with him* so thats kinda explains why Ocelot is supporting Snake in MGSV
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Big Boss :
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The Man the Myth the Legend, Big Boss also known as Naked snake or John, Him and solid snake are completely different person which is obvious ( Solid snake is the guy with blue bandana), You will know the reason why he is called " Big Boss" after you finish MGS 3 anyways Big Boss started his own military group called " soldiers without borders " back in 1974 with kazuhira miller . Kaz and Big Boss kept upgrading and building " soldiers without borders" or " Outer heaven" until a man came called Skullface destoryed everything
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kazuhira Miller :
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Just like i said Kaz and Big Boss started a military group , Kaz trusted Cipher without Big Boss knowing so that caused trust issues between Big Boss and Kaz, Cipher's Rouge agent Skullface betrayed Kaz in ground zeros which caused him to say the iconic line "THEY PLAYED US LIKE A DAMN FIDDLE"
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XOF :
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Not too much to say about this unit other than the leader is skullface and it works with cipher the main villain of the game
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Outer Heaven :
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Outer heaven is a military organization led by Big Boss which is free from the system and stands againts Cipher aka The patriots
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Motherbase Staff :
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Well they are not an Iconic characters in the series but the reason that motherbase staff respect Big Boss is because of what he did back in the time back in 1974 or even back more, Big Boss is even feared by his enemies
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Skullface :
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Skullface only appear in 2 games ( ground zeros and the phantom pain) all you need to know that skullface knows Big Boss since 1964 ( when snake was doing his first mission), i dont want to say alot about skullface because i dont want to spoil the story
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Dr. Huey emmerich :
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Dr emmeirch was a Metal gear designer he designed Metal gear Zeke back in 1974 and other metal gears, Big Boss met and saved him in 1974, also he was married to doctor strangelove
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Dr. Strangelove :
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Dr. Strangelove was an AI research scientist, responsible for the development of the Mammal Pod AI, as part of the Peace Walker Project in the 1970s. As her nickname implies, she had "a strange love"; a reference to her sexuality.and also she was married to huey emmerich