Hello there!
So, where the people settled, the place was very swamp. The water was very bad to drink. A lot of people got seawater poisoning, because they were drinking seawater. They also caught a lot of infections, and got poisoned. There were bad problems with mosquitoes and other bugs. In the area, there was not a lot of animals, so when they came, soon after there were no animals to hunt for.
Hope this information is enough.
<span>-Sammy</span>
Anime is "cartoon"
but we(weebs) hate normies saying that ist cartoon cuz for normies "cartoon" is "for kids only", those normies doesn't even try to watch or urderstand anything for no reason.