You probably forgot about it, but it's mentioned in the first MGS that Snake killed Big Boss. Big Boss (aka Venom "Punished" Snake) is the "father" of Solid and Liquid Snake (they were both made from his genetic material), and yeah, he spends a whole lot of time getting his ass kicked, but he's still the baddest dude of his time.

He actually didn't kill him. He thought he did, but Big Boss survived and was recovered by the Patriots. At the end of MGS4, Big Boss confronts Solid and turns off Zero's air breathing device.

BIG BOSS IS A GOOD BOY
HE DIDNT DO NUFFIN

Big Boss is the father of Liquid and Solid Snake, Venom snake is the medic in the chopper during ground zeroes.

These "attributes" are petty. One-eyed Snake is actually human. Solid Snake was made in a test tube to be the mirror image of Jack; Naked Snake(MGS3). Solid Snake (David) attempted suicide before Big Boss was like "Nigga you stop that shit. I ain't letting my son go out like no puss." They're both cool in their own regards, it's just that one was a time bomb at one point and the other can ROCKETU PAWNCH at will.

pretty close*

Fuckin' oh well

Its making Big Boss look like a chump and Solid Snake look MLG pro but the facts are technically accurate. I also thought they were the same person until i got halfway through MGS3. Damn Les Enfant Terribles