Event
The Skrull proposed a test to determine which race should join their federation by leaving representatives of the Kree and the Cotati on a barren planetoid in the Milky Way galaxy, Earth's moon. Returning a year later the Kree had constructed a magnificent blue city while the Cotati had cultivated a beautiful garden. This region developed by the two races would come to be known as the Blue Area of the Moon. Choosing the Cotati to join their federation, the outraged Kree slaughtered the Skrulls and Cotati, seized the starship and returned to Hala. Due to the immense distance between the Hala and Skrullos systems the Kree had time to master the stolen technology before the Skrulls could retaliate.
Becoming a star-spanning empire, the Kree eventually set their sites on the Andromeda Galaxy, attacking Skrull outposts and finally Skrullos itself. Faced with this hostile enemy, the Skrulls were forced to abandon their peaceful ways and became an increasingly militaristic society. The conflict between the Kree and Skrull raged across galaxies finally coming back to the star system where it began.
With several accounts of alien activity on Earth it was only a matter of time before the planet's heroes would become involved in the conflict known as the Kree-Skrull War.