David was first encountered by Heroes Unite during his rampage through Paris. SHELL and Relik attempted to stop him but were unable to. Inside David was an unknown metahuman, his out-of-control powers responsible for creating David as an animated shell and trapping him, scared and in pain inside the giant.
With the last-minute assistance of Amalgam, SHELL and Relik blasted David open. Proxy used the powers she had duplicated from young girl Claire Despoir to sever the soul from its mortal coil and killed the unknown metahuman, freeing him from his suffering.
It was later revealed that "David" was one of a number of victims of Kreed the Corruptor. Kreed had corrupted his soul and unleashed his metahuman ability while he was a tourist viewing Michaelangelo's David. This being the last thing he saw before becoming trapped may explain his giant shell assuming the form it did.
David was huge and incredibly tough, easily able to withstand the combined blasts of both Relik and SHELL. When damaged he was able to absorb nearby debris to reconstitute his body.