Treacherous Behavior?

On Cain, the dominant species, the Yildivans, has no social group larger than a family. Cubs leave their parents as soon as they are old enough. A young male, accompanied by his Lugals, claims a territory where he is later joined by one or more young female Yildivans. Each household is a patriarchal forest settlement in a hut or cave. There is occasional barter, joint hunting or conflict between individuals but that is all.

Lugals are like: if, instead of domesticating and breeding wolves, early homo sapiens had domesticated and bred another hominid species; thus, bipedal, talking dogs, so many that each Yildivan, even each child, has several.

Yildivans are hunters, artists, magicians etc whereas Lugals are laborers and messengers but, if intelligent, boss other Lugals and teach the Yildivan young.

"'The Yildivans are the creators and innovators, the Lugals the communicators and preservers.'"
-Poul Anderson, David Falkayn: Star Trader (New York, 2010), p. 287.

And both species are biologically adapted to these roles, thus incapable of questioning or defying them. Essentially hunters, the Yildivans practice primitive cultivation and metallurgy and farm for fabric. The Yildivan Shivaru chases a large horned animal, jumps on its back and kills it with an ax. Then his Lugals cut and carry the meat, edible by human beings but lacking some vitamins.

Having been friendly, the Yildivans suddenly buy modern weapons, leaving Lugals as security, then attack with the weapons, aided by the Lugals. This would be treacherous behavior, by their standards as well as by ours, except that they have come to believe that the human traders are the equivalent of wild dogs. See here.