>>106321725Okay, buckle up
The Kree lived on a planet with sentient plants called the Cotati. The kree ignored them because, as carnivores, they didn't give two shits about plants
The Skrulls had developed space travel and were going to inhabitated planets, offering the locals Skrull technology, knowledge, and protection in exchange for open trade and diplomatic relations. Seeing two sentient species inhabiting the same planet, they offered a competition.
A group of Kree and a group of Skrulls were put onto separate moons and given Skrull tech, infinite resources, and a year. The Kree built a large, gleaming city, but the cotati completely terraformed their moon into a lush planet.
The Skrulls favored the cotati, so the Kree killed them all, total genocide, hoping to tip the scales in their favor. The Skrull delegate was horrified, and declared the Kree unworthy of Skrull knowledge.
The kree murdered him and reverse engineered his ship, forming the Kree armada, and declaring a war of extinction on the skrulls for the insult of not wanting to hang out with a bunch of fucking homocidal cavemen.