- "It is the sum total of all seven Evils housed within one body. There is an ancient legend, known only to a few, of the great Dragon, Tathamet, who was the original embodiment of evil. The legend says that he was ripped apart during an epic battle with Anu, and that the Burning Hells are composed of his remains."
- Tathamet was the second being to exist in Creation. The counterpart of Anu, the first being and a personification of light at the time, Tathamet's creation and death led to the birth of the Burning Hells.
According to various myths, Anu was the first, and for a time, only, being in Creation. Seeking a state of total purity, Anu cast all evil from itself. However, these elements could not exist in a state of separation, and coalesced to form a new being: Tathamet, a seven-headed dragon that was the sum total of all evil. Though separate entities, Anu and Tathamet were bound within the Pearl that contained them. There they warred against each other in an unending battle for ages uncounted. Neither could gain the upper hand and finally, after millennia of combat, they delivered their final blows, their energies depleted. The resulting clash of light and darkness was so vast and terrible that it gave birth to the universe itself, killing them both.
Tathamet's blackened, smoldering husk spiraled into the lower darkness of reality. From his putrid flesh arose the realms of the Burning Hells, and the race of demons that arose from them like maggots from a corpse. Additionally his seven heads spawned the Great Evils. The strongest of his maws gave birth to the three Prime Evils, while the four lesser heads gave birth to the Lesser Evils.
The Dragon Reborn
- "Then Diablo seeks to become the Dragon once again?"
"In a manner of speaking, yes."
—The Nephalem and Tyrael
Uncounted ages later, Tathamet, in some sense, returned to the face of Creation. Diablo, the Lord of Terror, was able to combine the essences of the other six Evils into his own body, becoming a singular Prime Evil. While he was defeated by the Nephalem in Heaven and his spirit returned to the Zoltun's Black Soulstone, Diablo remained a singular Prime Evil. And through the destruction of the stone at the hands of Malthael, released into Creation once more.
- Tathamet is possibly named after Tiamat, a chaos monster and the primordial, draconic goddess of the oceans from Babylonian mythology. Tiamat mated with Abzu, the god of fresh water, giving birth to the gods; this parallels the clash of Anu and Tathamet creating the universe. Tiamat is later killed by Marduk, and her divided body form the heavens and the earth, like how Tathamet's body became the foundation of the Burning Hells.
- Tathamet's depiction and namesakes are possibly influenced by the Beast and the Serpent, two beasts who bring about Armageddon in the New Testament. There are other myths in mythology throughout the Middle East depicting a seven-headed dragon or serpent as an evil being of destruction.
- The relationship between Anu and Tathamet may be based on Ahura Mazda and Angra Mainyu of Zorastrianism. Ahura Mazda, the counterpart of Anu, was the original "uncreated" god who created Angra Mainyu, the counterpart to Tathamet, by purging himself of all his evil. Just as Tathamet is a being of destruction and the "father/grandfather" of all demons, Angra Mainyu is a being of chaos and destruction who created demons to battle Ahura Mazda.
- Tathatet's nature and backstory can be compared with Vaatu from Avatar franchise. They also share few things in common albeit they also different at the same time:
- Notable similarities with Vaatu:
- Much like Vaatu and Raava, Tathamet was trapped in a brutal conflict with Anu in the past before mankind born.
- Both Tathamet and Vaatu mainly represent Chaos and Darkness.
- Both Tathamet and Vaatu have the power to corrupt other beings to their side (Mortals and some angels for Thatamet and Spirits for Vaatu). Although, Tathamet's fullest extent of corrupting powers are only shown in Diablo 3, where with help of Zoltun's Black Soulstone and his sibling's essence, Diablo gained both aspect and powers of Tathamet, and use the said powers to corrupt newborn angels and turn them into abomination that immediately locked up during his siege in Heaven. Despite this, as separate entity, Tathamet's essence (better known as Prime Evils and Lesser Evils) still retain their corrupting powers, able to corrupt some humans to their side, like Vaatu did to spirits.
- Both Tathamet's and Vaatu's essence can merged with a human body, in which can affect their powers.
- Difference with Vaatu:
- Vaatu can resuciate himself wholly after being destroyed, while Tathamet cannot, as Tathamet's essence split into demons with it's aspects becomming the Prime Evils Mephisto, Baal, and Diablo, and the Lesser Evils Andariel, Duriel, Belial, and Azmodan.(Though interestingly both the Prime Evils and Lesser Evils can resurrect themselves after they die.) And the rest of it's essence transformed into Hell since his destruction.
- Tathamet and Anu used to be a single being while Vaatu and Raava are seperate entitities.
- Tathamet's and Vaatu's final fate after their conflict with their light counterpart was very different. Tathamet and Anu effectively destroyed each other, though their separated essence still fought each other, While Vaatu was initially imprisoned, and later purified and likely returned in the future.
- Notable similarities with Vaatu: