Leviathan

The Guardian of the Realm of Water and Ruler of the West, Leviathan is believed to be the largest creature on IIo. The Leviathan is unique amongst the Ursan Mystical Beasts in that she is always referred to as a female (the five other beasts are usually referred to as both male and female, revealing the ignorance of the people that wrote the legends…with the exception of Behemoth, who is almost always referred to as a male). Her progeny are the race of the sea-dwelling kraken, and the single amphibian Tarasque. Leviathan lives beneath the ocean waves, and her rise to land is one of the signs of the apocalypse in Ursan legend.