The “natives” aren’t native at all. They were invaded and driven from their homelands in a Trail of Tears like manner. They were allowed to settle in this incredibly dangerous mountain by a country, but they had to renounce their old god, and in order to protect the country they joined, have to hunt giant magic boars that breed so quickly, killing 50 a day hasn’t dented their population in the past 80 years they’ve lived there. To prevent the magic boars from going hungry and attacking nearby farms, they are forbidden from harvesting edible fruit or vegetables from the mountain. So not only do the boar hunters go hungry and starve, they’re prone to getting murdered by their own quarry. Regarded as a minority or barbarians, the country that accepted them actually fears them for their monstrous strength, and the boar hunters keep their problems to themselves, out of a sense of pride, and a duty to do their job, or die in the forest for being weakness.
The isekai’d mc, being an outsider is an absolute advantage. Being stranded gives him the excuse to enter the settlement. Being foreign hints to the border city citizens the boar hunters may not be as savage as the let on. A bridge between the misunderstanding and the misunderstood.