Adonalsium

Adonalsium is a mysterious term used in the cosmere, which could refer to the power of Creation or a god. It has not been revealed what Adonalsium explicitly is, but its power is seen in the Shards of Adonalsium, which act as imperfect gods in the cosmere. It is heavily implied there are sixteen Shards, but this has not been explicitly confirmed.

It has been confirmed that Hoid was there when Adonalsium Shattered.

Shards of Adonalsium

After Adonalsium shattered into its present form, the pieces were given to or taken by individuals that then had the powers of the aspect of the Shard of Adonalsium. These people tend to act like imperfect gods, capable of creating and destroying worlds. Many of these "gods" give specific magical powers to the people on their worlds, and most of Brandon Sanderson's novels take place in one of these planets. The nature of the common people's powers is modeled after the power of the Shard in question. For example, the Mistborn series has powers based on metal, since the two Shards used to create the Mistborn world are physical in nature (Ruin and Preservation).

The existence of a single origin of these shards have been hinted at in Sanderson's novels:

“I sense shards of something long ago, a fractured presence, something spanning the void.

I have delved and searched, and have only been able to come up with a single name: Adonalsium. Who, or what, it was, I do not yet know.

”

—Sazed, emphasis added

Another example is the El camino de los reyes epigraphs, which mentions that:

“Ati was once a kind and generous man, and you saw what became of him. ”

—The Letter

Ati was the name of the person who held Ruin before being killed by Vin holding Preservation at the end of El Héroe de las Eras. Intentionally killing Ati went against the intent of Preservation, but as Vin had not yet become attuned to it, she was able to use its power to her own ends.

It is also possible that those who take the power of a Shard may be able to resist this change to their personality by force of will, like when Sazed gained the powers of both Ruin and Preservation:

“[Ruin and Preservation] threatened to annihilate each other.

And yet, because he was of one mind on how to use them, he could keep them separate. They could touch without destroying each other, if he willed it.

”

—Sazed's revelation on the Hero of Ages

How long, or under what conditions, a person can keep their own will is unknown.

Trivia

The name Adonalsium may be derived from a Hebrew name for God, Adonai (meaning "the Lord" or "God", literally "my Lord".)