Leviathan

Slumbering under the Mercutio lake of Myrduriin, a gargantuan automatonic creatures sleeps. Waiting to awake and raise havoc, as it had done hundreds of years ago, when the dwarven had still been a race

The leviathan is a 25 meter long Dragon/Snake being, half of its body is also automatonic. The dwarves found the dead creature under a boulder, they removed the boulder and salvaged the body. They used the powers of Avna, and there intelligence to bring the creature back to life. After that it was used as a war machine to conquer kingdoms. Its most famous battle is the battle of the Titans spear, where Galdor Bacc slayed the leviathan with his spear "Titan." After it was slayed, Galdor's army threw it in the Mercutio, where it has been for several hundred years. Just laying there, rotting, flesh eating away.