The Kree are a scientifically advanced alien race with a galaxy-spanning empire. Because they come from a planet with higher gravity, the Kree are also significantly faster, stronger, and more durable than humans. The Kree are fascinating because, despite their physical and technological superiority, they're also genetically stagnant. This potentially means that you have a ruthless, intellectually-driven species that's constantly on the verge of extinction. The Kree value their genetic purity to the extent that reproduction outside of the species is a strict taboo. While the Kree look like an ideal threat to the Fantastic Four, there's just one problem; they've already been featured in Marvel's Guardians of the Galaxy, and are responsible for the creation of both the Inhumans and Captain Marvel, both set for future big-screen adaptations. My solution? Change the name, keep the rest. In fact, the Kree are also known as The Ruul, so Fox won't even have to try that hard to get around the copyright issues.