Void: The first Primordial and the Mother of Creation and Destruction.
All things were born from Void.
In the beginning, there was only Void,
endless nothingness, it was a paradoxical existence of there being an infinite expanse of nothing.
This was where Void herself lived, an endless expanse of nothingness, a quiet, calm existence. At first, Void didn't have a physical form, just a concept, an expanse.
But eventually, over what would be considered Millennium, she grew tired of just "being" so she created a Body, the first thing to "exist" the physical manifestation of Void.
This action caused a ripple effect, with Void no longer being an infinite expanse, and instead centralised into a single point that gave way to "Existence" coming from her new "womb" came Creation, born from Void Creation came to be, and with Creation came its opposite: Destruction.
Of course, due to Void now being centralised a new "Expanse" was created, Oblivion was created. A Dimension consisting of infinite nothingness which she could reside within whenever necessary.
Most of the time Void would instead watch over her children, watch as they squabble with one another and intervene if they got too rowdy, she actually quite enjoyed raising the two despite their complete opposite beings.
Bits of her power of void would always leak out while she was in "Existence" instead of Oblivion, her power mixing with Creation and Destruction caused many things to naturally form without Creation having intended to make them, such as planets and stars.
Over multiple Millenniums the once cold Universe that her children resided in became warm, however as time passed and she slowly stopped watching her children more and more, believing them to be mature enough to handle themselves, she found herself locked within Oblivion, unable to escape, her own power being used to keep herself locked within, and Destruction was also locked away within Oblivion with her, Creation had betrayed them both if you could see it like that.
Void, however, holds no grudge towards Creation, she simply wishes to leave Oblivion and see what he has created. One could see her as a proud mother but Creation sees her as a threat to his reign.
However the seal on Oblivion is slowly weakening, it was always impossible for Creation or Destruction to permanently keep her locked away. Afterall she was far stronger than the both of them combined, their powers couldn't harm her or affect her, as you can not destroy what doesn't exist and you can't create something from Nothing. But she could erase them both with ease if she ever wanted to.