In the original reality of Mirai Nikki, Yukiteru and Yuno managed to get together after the former's victory in the Second World's Survival Game. Having literally shattered the boundaries between the Second and Third Worlds, the Third World version of Yuno with memories from the First World version of herself would once again reunite with her beloved. The two would soon rule together as gods.
This, however, is not that original reality.
In this reality, a far more cruel fate awaits.
After having yet again failed to save both herself and Yukiteru from the horrific reality of the Survival Game, Yuno's mental state had reached an all time low. Her own failures led to her being driven to this unrelenting tipping. She now understood that if she recycled the Survival Game yet again, the same result would come forth. Bringing back others from the dead is impossible. No matter how many times the pinkette tried, victory would never be hers to wield. Yukiteru would remain dead. The world would still be erased. Deus still dies. Therefore, at her wit's end, she accepted defeat. Her endeavors with Yukiteru came to a heartbreaking end.
But what was she to do? Having killed, lied, tricked, and so many more gruesome things, there was not much for her to accomplish. The only thing Yuno can do is become the God she is meant to be. Even that was difficult. Without Yukiteru, her life had no meaning. The one stability in the God's life would never be with her. It drove her to the brink on countless occasions, obliterating what very little sense that remained. Once again, the question of what to do lingered consistently in that tormented mind.
Soon enough, after ten thousand some odd years of sulking and pondering, a decision had been made. Was it far too late to consider things? Possibly. Alas, such a thing didn't matter. Yuno ultimately decided upon starting fresh with those new powers. With her happiness taken away, it's only befitting for her to eliminate the happiness of others as well. Destroy it, obliterate it, annihilate it, and kill it. Yukiteru's absence might have broken Yuno Gasai, but in return, a ruthless God of Time and Space would soon be born from the ashes of worlds before her....
ADVENT OF GOD.
Domination over Time and Space: Yuno's status as "God of Time and Space" is not just for show. Just like how Deus Ex Machina ruled the First and Second Worlds as its pillar, Yuno holds the same power. Without her, the universe would crumble into dust, similar to how Deus would've left her previous worlds had the Survival Game not come into fruition. As such, Yuno gains all of the powers he has, along with his near-omniscient mind. The only downside is her inheriting his weakness; the inability to bring others back to life.
Time Manipulation: The complete control over time, far beyond simply putting time to a crawl. Progression, regression, stasis, acceleration, skipping, deleting, and many other things that revolve around time can be utilized by Yuno.
Spatial Manipulation: The complete control over space itself. Whether it be the manipulation of gravity, the tinkering of distance, creation of portals, and so on, Yuno will be capable of performing such a thing.
Control Over Matter: The ability to manipulate and utilize matter as a weapon. Whether it be to create artificial limbs, energy attacks, construction, or actual weapons, Yuno has utilized this to her advantage on many different occasions. On top of this, she can also control anti-matter.
Complete Mental Immunity: Due to being trapped within Nyarlathotep's Shining Trapzohederon, Yuno was exposed to torture and horror that no living being should go through. However, due to the Outer God's mercy, she would not be killed. It is because of the extreme amounts of mental suffering she's been through that Yuno has grown total immunity to any sort of mind control and manipulation that may come to her.
Proficiency With Weapons: Before becoming God, Yuno was a hardened killer, being able to eliminate foes with a variety of weapons. These included the following: guns; rifles, knives, screwdrivers, hammers, katana, explosives, and axes, all with terrifyingly accurate precision.
HEADCANONS.
Yuno's interest in Yukiteru, along with her interest in love, has completely vanished. Even if by some cruel chance that she encounters Yukiteru, she will feel nothing.
Her mental state is nonexistent, both due to the events of the Survival Game and the actions of Nyarlathotep.
Although she no longer hesitates to kill others, Yuno will prolong fights to torment those she deems worthy.
As God, she only wears a tattered cloak with a hood. Every now and then, Yuno will wear her old clothes.
Various encounters with entities in the Multiverse have strengthened her battle experience and mind.
Her Yandere tendencies no longer exist.
Her primary weapons in close ranged combat are a katana, a knife, and an axe.
In progress.