Boring
The ship carrying all the soldiers did not land on the planet. In fact, it did not even enter the atmosphere, for the planet was infested with hordes of mindless yet violent aliens. They were one of the many species that had been bred especially for wars against planets.
The Fuegan were, in fact, not the first to use such tactics, though currently they were the ones employing it the most in the origin realm.
The concept was simple. Once any civilization reached a certain level, and grew enough, they would gain the means of genetic manipulation, whether through technology or spiritual techniques or something else. With such advancements, there naturally came military applications.