Stelios tried and failed to possess a clone of Legion so her failure is not special. But he considers her to be worse than being foolish for attempting it at all. She is a clown that isn't funny who then decided to do something dangerous to prove that she is funny. She played with her consciousness without knowing what she is getting into. That is literal because she actually left her body and entered his in her attempt to enslave him. She didn't know what she was getting into at all.
The consciousness of a transcendent is their most important asset apart from Origin energy. They can lose their body but they will regenerate it as long as they are still alive. Their consciousness is contained within every part of their body so a transcendent will survive their head getting crushed. The consciousness can be likened to the identity of a transcendent. It is what keeps their body and soul together.
Her divine ability allows her to use her consciousness to manipulate the consciousness of others through her eyes. As they say, the eyes are windows to the soul. Unfortunately for her, she met a consciousness that she cannot manipulate. She met a mountain of a consciousness and paid the price of gaining entry into the core of that mountain. She had to meet the Mountain within the first Mountain.
She is far too weak to manipulate a consciousness that can manipulate the law matrix of the world. His mind has survived going into the world of concepts and back. His mind swallowed parts of the law of order of a world god to give to Legion-7. He is already too much for her to handle much less Legion-7 and himself together. Her consciousness is but piecemeal to him.
Her attempt might seem less significant than what Stelios tried to do with Helios but it is not. Stelios tried to use the gap between Helios's consciousness and his body to eject Helios's consciousness and possess his body. Stelios was also highly ignorant of who he was messing with.
This lady tried to change his consciousness itself. She didn't want to gain control of his body but wanted to reshape the very fabric of his mind and she knew full well who he is. He is not some random person. He is the child of the plane. That should have counted for something. Ignorance is not a valid excuse for her. She is plainly suicidal.
She probably did it because she thought she had nothing to fear. The rules of the competition emboldened her. Her attempt to control him is more invasive and more stupid. Stelios was able to escape because of the gap between his body and soul but there's no gap for her to escape through. He has a soul body now due to the fusion of body and soul. Her body thus fell apart without a consciousness to hold it together.
He looked within himself to see what has become of her. The giant eyeball with several eyes on it has reprogrammed her consciousness and is using it to intrude on the core of the world fragment. Legion-7 modified her using the law of order of the sage making her consciousness look like a string of instructions similar to the law matrix of the arena. This will ensure that the resistance of the core will be significantly lower and he will be able to get easier access to it.
He has finished mapping the law matrix of this world fragment before he fought the last boss. He got what he wanted to get. He got power and he got knowledge. It is the same power that he used to strip those two of their power. He used WRAITH OF DEATH: GHOST OF THE FUTURE to bring about the effect of their future fight into the present. His understanding of time made him realize that everything that can happen is currently happening including both the future and the past.
His eyes aligned a future where he destroyed them to the present. This should have caused their death but the brand on their bodies saved them. That brand is under the control of the core of the arena so he can't control it. What he can do is influence the privileges of the brand on them.
One of the privileges is to be saved from death and respawned somewhere else. He can't change that since it is not changeable. Another privilege is the power system of this world. He can't remove it either but he can reset it since it is a changeable factor.
The power system empowers the competitors by a certain amount based on their rank. He can't remove the augmentation entirely but he can reset the rank to 0 which eliminated the empowerment of this world entirely. It must have been very hurtful for them to lose all their progress but they can regain it if they put in the effort. What he did to them is temporary.
That is one of the powers he got from his tinkering with the law matrix. He found a lot more beyond his reach when he was done with it. He could be satisfied with what he has achieved or he could seek out more.
The power he got is not permanent. He will lose it when the competition ends and he has to leave the arena. There are all sorts of limits on what he can do with the power too. Those are already enough reasons to convince him to seek out more.
He doesn't really need a reason to seek out more power. He will always be seeking out more power and only power if he can. But a reason to seek out power is always great. He can use it to explain his current actions to the sage in case the sage is mad about the death of a competitor.
He will start his exvuse with, "She fell into my consciousness. It wasn't my fault at all."