Luna Kamaria
Luna's plot wasn't just to create enjoyment for Black. Normally, the cross between two worlds left any human stunned, and weak enough for any soul (if they had two) to take over. The wolf demoness wanted see how Mikoto's other half would be like, and what she would have to do to retrieve it. Luna began into a sprint, running as fast as possible. Suddenly, darkness enshrouded them. It was only for a second, before a barren red landscape appeared. Many black creatures soared in the skies, while others slithered below. Luna did trample one while entering, but it wasn't as though that demon would be missed.
So what your saying is that when in the demon world, black's other half will take over and when in the human world, black would take over?