MODOK is sort of a villain without an Arch-enemy. He's best described as "Avengers solo" villain, as he almost always faces Avengers members, but rarely faces the whole team. He was created to be a Captain America villain in Tales of Suspense #93, and served as Cap's main rogue when Red Skull was on the bench. After a couple of years that saw the creation of most of Cap's Modern Rogues gallery (Viper, Doctor Faustus, Batroc The Leaper, Arnim Zola, Helmut Zemo) MODOK became an Iron Man villain, and after that focused his attention on the Hulk. Still, the floating man with the 12 foot head managed to tangle with just about every Avenger/ ex-Avenger who wound up getting a solo comic. So where would you stick MODOK in the MCU?