Yu

Yu was the being of what will happen, and the brother of A. Yu and A were opposites, and Yu's ability of knowing what will happen feared A, causing him to split from the Void.

A's Departure
Once A decided to leave the Void, thus splitting it, A and Yu were destroyed. However, as A was the cause of the split, when Yu was destroyed it managed to throw itself into the planet Aduwey, allegedly creating the Glass of All, a powerful artifact that could see the future.

The Great Failure
As A's intent was that splitting the Void would kill Yu, thus rendering the impossibility that what will happen could be known to disappear. This was however a failure in As' part, as Yu knowing what will happen meant it knew A would split from the Void, thus Yu threw itself into Aduwey to render As' attempt useless.