Depends on the metal that is absorbed, as he can only carry one type in his veins at any given time. Ex: If he absorbs steel, then his blood can become Steel-like. It'll still be flexible, but it would be more so with a metal-like gold, able to make sharp turns and such to take on aan opponent, yet not as durable as if he absorbs steel. This power will require intense use of wikipedia, I'm sure.