Cielo Island, the bane of travelers, is also known as the Pit of Ophidian. (See
the map of Thamaltis to find out where Cielo Island is.) You smart people who just googled that could tell me that that means the Pit of the Snake.
Why is Cielo Island called such? Because it is infested with snakes. Snakes with such poison as could knock an elephant off it's feet with one bite - if there were any elephants on the island (which there aren't).
These snakes are called blacksnakes, because of their color, but they are no ordinary blacksnakes. Oh no! No, these blacksnakes are the spawn of the Aru Tonga, the Great Snakes. The Aru Tonga are 100 feet long, and five to six feet thick. They are hundreds of years old, as it takes them at least 50 years to mature into adulthood. They live in the tunnels and caverns they carved out of the rock face, and bring forth many young, the blacksnakes. It is because of the Aru Tonga that the island is uninhabitable, though no doubt the presence of the blacksnakes helps.
The blacksnakes (and, consequently the Aru Tonga) have an affinity to water, and often swim in the sea round and about Cielo Island. They rarely wander far from the island, though, which is just as well for Agatha Island, Cielo Island's close neighbor.
Cielo Island is divided into two parts. The side closer to the open sea is much more rocky, and the side closer to the coast of Thamaltis, is wooded and swampy, affording the blacksnakes their hunting ground.
In instances of storms, ships occasionally stop off of Cielo Island for repairs, but no more than absolutely necessary, because of their superstitious fear of the Aru Tonga, the masters of poison, the Ophidian.