Scratch one more cool character off the Marvel Cinematic Universe list as Kang The Conqueror is owned by Fox Studios.
A hopeful fan questioned Guardians of the Galaxy director James Gunn about the use of Kang on Facebook, with Gunn replying the character is owned by Fox.
Gunn also let it be known Fox owns the rights to the alien race, the Shi'ar, as well; so both Kang and the Shi'ar won't be appearing in Guardians of the Galaxy 2 or any Avengers movie any time soon.
Gunn did let it be known they chose the characters that are appearing in Guardians of the Galaxy 2 a while ago.
Regarding Kang The Conqueror, the time-travelling Avengers foe first appeared in Fantastic Four #19 in 1963 as Nathaniel Richards/Rama-Tut, which is why Fox probably owns him. He first appeared as Kang in Avengers #8 in 1964.
Likewise, the Shi'ar first appeared in X-Men #97 back in 1976, and we can also guess Fox probably also owns the rights to the members of the Imperial Guard with Gladiator and such.
I guess the good news is that both Kang and the Shi'ar can appear in Fox's X-Men and Fantastic Four movies.