5. Moondragon
Moondragon, like so many great Marvel characters, has a rich history. Before she became Moondragon she was Heather Douglas whose parents were killed by Thanos. She survived the attack and was taken back to Thanos' home of Titan to be raised by his father, Mentor. Meanwhile Heather's own father's soul was used by Kronos, one of Earth's Eternals, and put into a new body to create Drax the Destroyer (played by Dave Bautista in the upcoming Guardians of the Galaxy movie), a warrior designed to kill Thanos. While at Titan she was trained by the Shao-Lom monks to utilise her latent telepathic powers. One of her first opponents was an entity called the Dragon of the Moon whom she thought she defeated, taking its name for her own to commemorate her victory. Known for her powerful telepathy, Moondragon has been an Avenger, a Defender, and an unofficial Guardian of the Galaxy, and has fought Thanos and Ultron on separate occasions. She's also been a one-time custodian of the Mind Gem, one of the Infinity Gems, which was seen in The Avengers movie used by Loki to brainwash people (speaking of which, Moondragon once brainwashed Thor into being her personal love slave!). The Marvel movies seem to be headed in a more cosmic direction and, coupled with the existing framework that fits right into the character's history, Moondragon would be a great addition to the MCU (just don't mention that she previously called herself Madam MacEvil!).