The Wyvern of Hades is a MYTHICAL pet that is obtainable from the Hell Egg with an unknown chance of hatching. At one stage the Rainbow variant of this pet was the strongest pet in the game.
The latest Pet Simulator X value list for Wyvern of Hades can be found below:
💎 46,500,000 (46.5m)
💎 147,000,000 (147m)
💎 344,000,000 (344m)
💎 620,000,000 (620m)