Artist/fans will do what they do. It is their choice. Frankly I've already seen stuff like this not long after SotN became an overnight sensation. There has been numerous fan manga, images, etc. out there that have depicted Alucard, Richter, and Maria getting into all sorts of XXX rated stuff. This is just adding to that already saturated pile of fan service. Personally it goes against Alucard's nature as he did make the choice to remain single due to his cursed bloodline (not wanting to possibly spread it). A message that Warren Ellis obviously never got.