Board Thread:Metal Gear Solid V/@comment-180.191.222.139-20140223073630/@comment-66.57.204.89-20140321194116

^^^

Exactly.

I'm guessing Zero had a hand in either the attack that took his parents' lives or the proceedures that stripped him of most of his memories. I believe everything in Ground Zeroes was some kind of orchestrated plan to get Snake more involved with the search for Cipher, to find Zero.