4. Grim Reaper
Marvel ComicsIt would be very interesting if there was a direct link between Ultron and HYDRA, given HYDRA's prominence in the Marvel Cinematic Universe, and the Grim Reaper (not the actual figure of death) could be a cool way to get the two evil entities connected. The unlikely pairing came together (the Ultron-12 version of the robotic character, at least) in a bid to destroy the Grim Reaper's brother - Wonder Man - who obviously doesn't exist in the Marvel Cinematic Universe at this stage, so that motive would have to be changed on screen, but if the Grim Reaper was to approach Ultron as HYDRA's representative in a bid to forge some kind of alliance, it would be a cool nod to the little arrangement they had in the comics. The Grim Reaper is actually a pretty cool character to boot. In his original incarnation, he was an ordinary human with a genius for all things technological. His trademark weapon was that of a "techno-scythe", which he wore on his right hand. It had the ability to spin at rapid speed, making the weapon usable as a high-speed propeller blade buzzsaw, a protective shield, or an improvised helicopter. He later gained some mystical abilities, giving him a number of esoteric powers and augmenting his physical statistics. His introduction in to the Marvel Cinematic Universe could mean he may be utilised as a villain in, for example, the Agents of S.H.I.E.L.D. television series in future.