It could be called a tradition of sorts, dating way back even before the Vikings.
A lone ship crossing a vast, desolate expanse, searching for some new land with new opportunities and new wealth.
Most never make it. Some that do find only another kind of desolation; but one out of hundreds will finally hit the jackpot.
They find a new land of strange wonders and exotic wealth and they collect some of these new treasures and take them home to be laid at the feet of their chief/king/tyrant/smooth-talking-bastard; with the promise that there was plenty more where that came from.
This leads to great expeditions in the wake of that first, risky lone voyage and the new land is quickly settled.
If this new land is uninhabited, they call it 'Colonization'. If there happens to be an indigenous people living there, it is called 'Invasion'.
The settlement of Adjes would have come under the latter category had the starship not failed to attain an orbit around the planet.
Her crew managed to avoid burning up as they entered the atmosphere for an emergency landing, but even that almost ended in catastrophe....
As the survivors surveyed the wreckage strewn across the landscape, they realized that they were going to be staying there for a long time and that they would be at the mercy of whatever providence decided to throw at them.
As the native people of Adjes watched the humans from their hiding places, they realized that providence had given them something their world had been lacking since the dawn of time.
But that was three, no, four generations ago and things have progressed far from that moment in time.
As has the relationship between the humans and the Adjezezii.
Take 'Kop', for instance.
Her great grandmother was an entomologist who could speak seven languages. Kop can't even speak one. Nor can she read, or write or even count. That's what happens when a people are kept bound and gagged and denied the means of communication and education for three generations or more. Instead Kop fills the niche in the ecology of Adjes as the beast of burden the planet never had.
Humans make good domestic animals of Adjes and are highly prized. Which is why the human population on the planet has been growing quite rapidly over the last two generations.
So from a certain viewpoint Adjes actually has been invaded by humankind... just not in the traditional manner...