At the beginning of the Kree-Skrull War, millions of years ago in Earth time, the alien Kree established a station on the planet Uranus, a strategic position between the Kree and Skrull empires. Through their work at this station, they discovered that sentient life on nearby Earth had genetic potential invested in it by the alien Celestials. Intrigued, the Kree began to experiment on Earth's then-primitive Homo Sapiens by splicing Arlok's DNA into Cro-Magnons. Arlok was an Eternal who was a follower of Uranos that had been dissected by the Kree.
Their goal was apparently twofold — to investigate possible ways of circumventing their own evolutionary stagnation, and to create a powerful mutant race of soldiers for use against the Skrulls. However, although their experiments were successful in creating a strain of humanity with extraordinary abilities, the Kree abandoned their experiment for reasons which are not yet clear.
Their test subjects, The Inhumans, went on to form a society of their own, which thrived in seclusion from the rest of humanity and developed advanced technology. Experiments with the mutagenic Terrigen Mist gave them various powers, but also caused lasting genetic damage and deformities. This led to a long-term selective breeding program to try to mitigate the effects of these mutations. Their city of Attilan has frequently been relocated and rested for a long time in the oxygen-bearing Blue Area of the Moon.
The once-secret existence of the race came to light among the general public as the Inhumans interacted more often with many of Earth's superheroes — including the Fantastic Four, the Avengers, and the X-Men — whom they aided against threats such as Galactus, Ultron, Magneto, and Apocalypse. The Inhumans were led by their king, Black Bolt, and his royal family, consisting of Medusa, Karnak, Gorgon, Triton, Crystal, Maximus the Mad, and the canine Lockjaw. Both Crystal and Medusa were members of the Fantastic Four; Crystal also was a member of the Avengers.
Members:
Black Bolt
Medusa
Gorgon
Karnak
Crystal
Thane
Maximus the Mad