The number of villains in the Marvel Cinematic Universe is gradually growing. Those still alive as this is being written include Thanos, Loki, Leader, Abomination, Baron Strucker, Absorbing Man, Justin Hammer, the real Mandarin and various other characters in the Agents Of S.H.I.E.L.D. television series - and don't forget that the aforementioned Ultron probably won't be gone for good after Avengers: Age Of Ultron. Several more will be introduced in Phase 3 and what's left of Phase 2, so don't be surprised to see them join forces at some point in Phase 3 - after all, Phase 4 needs to be bigger and better than anything that came before it and what could be bigger and better than a team of supervillains going up against the Marvel Cinematic Universe's heroes. Of course, any live action Masters Of Evil line-up would be very different to anything seen in the comics, due to rights issues, but it would still be awesome to see.