Because the details of 20th Century Fox's licensing agreement with Marvel for their X-Men and Fantastic Four films have never been made public, it's unclear under whose purview certain characters fall. Now, Guardians of the Galaxy director James Gunn may have shed some light on who controls the Skrulls, one of Marvel's most famous antagonistic alien races.
According to Gunn, the Skrulls as a group are "co-owned" by Marvel and 20th Century Fox, meaning that both studios could use the characters in a film with some coordination. If accurate, this would make them similar to Quicksilver and Scarlet Witch, who can be used by both studios, with different versions of Quicksilver having appeared in both the X-Men and Avengers movies already.
Some specific Skrulls are at Fox. But the Skrulls as a whole are co-owned. https://t.co/2hJYkskLZ3— James Gunn (@JamesGunn) July 6, 2016
The Skrulls debuted in the pages of Fantastic Four, but were a key part of several major Avengers storylines including the "Kree/Skrull War" and Secret Invasion. The Skrulls almost appeared in the first Avengers film (as evidenced in animatics released after the film) but were switched to the Chitauri, an alien race that started as the Ultimate Comics equivalent of the Skrulls before being delineated as a separate and distinct race.
Gunn's tweet also makes it clear that certain specific characters may be controlled wholly by Fox; possibl characters such as Super Skrull and Lyja who debuted in Fantastic Four, and have almost exclusively been FF characters.
Gunn has disclosed such details before, such as when he claimed that Kang the Conqueror falls under Fox's side of the agreement, but those these reports have gone unconfirmed.