Arata's wish for a strong body that doesn't get sick or hurt was granted when he was reincarnated on what he thought was an uninhabited island. While there aren't humans living there, the island is full of Divine Beasts, Ancient Dragons, Vampires, and Monsters! Arata thought he was in a desperate situation right from the get-go, but apparently his strong body that doesn't get sick or hurt is just too strong?!

(Source: Square Enix)