The Serpent King wonders the caves of the Shinokey Mountains in search of Butterfly Bats. As far as I can tell he is the only creature on all of Carkayous that is immune to their venom. Just like the pilot fish of a shark, the Serpent King typically has 2 to 3 Vinick snakes following it around at all times nibbling up the leftover scraps from his previous meals.