The third Overgrown Oni, commissioned by OverLordOfNobodies! (Who, you should thank for starting this whole Oni thing in the first place....)
"The twelve ninja, now resurrected and free from the control of the evil Oni spirits that transformed and corrupted them into becoming the Oni Queen, had lived in relative harmony with each other, using their new powers for good. However, they did not realize that their destruction and resurrection did not completely obliterate their Oni natures. Instead, it had caused their bodies to permanently merge with the essences of each of their respective Oni, which were now benign extensions of themselves. Yes, the spirits were no more, but the twelve ninja were no longer mortal humans, either. They were now the “New Oni” and it is in the nature of all Oni to, above all else, desire and consume power.
With every conflict, they would grow more and more careless in their accumulation of power. Again, their bodies began to expand, absorbing mass amounts of chakra, becoming "Overgrown Oni." They knew that another merge would be inevitable if they remained in close geographic proximity to one another. So they all decided to disband and travel to the four corners of the land, where they would attempt to live in isolation and control their forms.
Tenten and Temari, due to their symbiotic relationship, remained the guardians of the Sand Village in close proximity to one another. Though they needed to spend more and more time apart from one another, lest the temptation of a permanent merge overtake them. They understood that this could have the unpleasant consequence of losing both their individualities and possibly relapse back into an uncontrollable monstrosity. When apart, they would spend many hours in deep meditation and reflection, becoming more in tune with the earth that composed their bodies. In time, they learned to absorb dormant power directly from the earth. This enhanced their individual strengths and caused them to become larger and even more powerful guardians than before.
As the years passed, most of the Oni grew content living in isolation. Soon, they outlived all who had known them. Centuries passed, empires rose and fell, and soon the Oni themselves vanished into myth and legend. Eventually, a new generation of primitives became drawn to their powerful chakras. Despite their protests, the people began to venerate them as mighty beings and protectors. Some of them even began to worship them as great demigods.
Though their ninja principles wanted to reject such worship, their Oni natures swelled with pride and hunger. Eventually, they settled on an internal compromise. After all, it is only natural for an Oni to want to dominate, rule, and become empowered! However, it would be different this time. This time, they would heed their ninja vows. Instead of selfishly draining resources and chakra to grow infinitely in power, their relationship with the people would become symbiotic. They would protect them and bring them good fortune, using their powers to benefit their adopted cultures. In return, the people must freely offer them their chakra, though sparingly and divided out among many people as opposed to draining everyone's chakra completely. This would give the people time to recover and, in turn, prevent the Oni from becoming too gluttonous.
And so, the New Oni (as they called themselves) lived in relative peace for years, being loved and feared throughout the lands they dwelled in. But perhaps, the day may come where they would have to unite their powers once again, should a greater evil manifest itself and threaten the world. And perhaps only the combined might of the New Oni can stop it!"
Really with that body and those spikes as well as how you cover her lower face makes me fill like she a real big time bruiser right now.