Gladiator

As a member of the Shi'ar race and an Imperial Guard with tremendous strength and numerous abilities, Gladiator is another character who could further expand the MCU into new corners of the comic book universe. He could make any current MCU superhero tremble (yes, even Hulk). In addition to his great strength, he can fly faster than light (which we haven't witnessed in the MCU); he's invulnerable (can withstand a supernova); and he has freeze breath, heat vision, and other abilities. He could literally be the strongest of them all.

His backstory is what makes him interesting: how he became a Praetor, how he was trained, his involvement with the X-Men"¦

We could actually see him co-starring in a Guardians of the Galaxy flick, if the character's rights hadn’t been sold to Fox.