He too is hiding himself. But his stealth is external. Anyone who can see past his cover of warped space can see him, but it will be difficult to do so because the way he warped space around himself makes him exist in a different dimension.
But she, on the other hand, is in the same space but cannot be seen at all. She is like the invisible spiritual fragments that are created when someone dies. It appears as if she doesn't exist at all.
He used this information to try and devise a plan. In his future vision, possibilities flashed by several times. They fought in those futures, with some leading to his victory and some leading to his loss. But most of them did not end quickly. The fight at the soul level went on for years once it started.
