Type/Species: Sea Serpent
Origin: Christian Legend, The Bible
Leviathan can be found in the Bible and is described as a creature whose power is far better than that of man. He is described as having eyes that shine as the rising sun, and his back was described as being made of a row of shields. 
In addition to this, it is said that when Jehova created life he also created this creature. On Doomsday, God will kill this dragon and this will be the end of the world. 
Though Leviathan is described as a Sea Serpent, it is often thought to be some type of dinosaur that was still around during the ages of the Bible. The creature is described like many of them, but it is noted that the Bible states plainly that "Out of his mouth go burning lamps, And sparks or fire leap out. Out of his nostrils goeth smoke," which means that the creature breathed fire. 
For more information on footnotes and references, please see the bibliography.