Something about this whole adventure makes me feel Kiromaru could be out to betray them. Perhaps Squealer is holding all the remains of his clan as hostages. It would also explain a bit of the ease of following them. I wouldn't put it beyond Squealer's intelligence to form multiple plans for contingencies, one of them being to make sure the humans can't fetch any secret weapons from elsewhere. A good way to prepare for that, considering the humans never leave their villages, would be to make a seemingly trustworthy guide available to them. Still, I'm sure Kiromaru hates Squealer's guts, so the mastermind needs to keep a close watch.
However, at the end of the day, I'm sure Kiromaru would have nothing against getting rid of humans. Humans weren't exactly good neighbours. He might not be as fanatical as Squealer, but he's still a man who would put his own people above everything else.