I think Void made the sacrifice. Gaiseric is probably branded and was meant to be devoured. Void was, I think, Gaiseric's Counselor and had the Crimson Beherit. He was the one who caused the capital's destruction, a thousand years ago. Gaiseric (who I'm positive is the Skull Knight) is certainly not one of the God Hand, regardless, and most likely not an apostle.