Board Thread:Metal Gear Solid V/@comment-188.39.86.173-20140318135708/@comment-6747658-20140623182835

My guess is, because it is rather well implied that ZEKE could have survived Mother Base's destruction, is that they fished it up and reverse engineered it to become that new Metal Gear that's shown in the E3 trailer.

Though then again, we see Snake riding a mini-gear in the previous trailer....maybe we get to have another Metal Gear vs Metal Gear like in MGS4, ZEKE vs Prototype REX, that would be something to watch.