The ten black panthers immediately charged at Gravis, eliciting quite some nervousness from him. He had seen how Jessy replaced her body with a shadow body before, and he knew that these had to be fake. If they weren't fakes, she would not be an average level four King.
Additionally, she would have used that ability before she got as heavily injured as she was now. She was only trying this approach since the others haven't worked up to now.
Yet, this approach proved quite effective. Gravis had no way to discern the real one. The copies emulated even the dripping blood from Jessy's exposed flesh. By all intents and purposes, the copies were flawless. There was only one real body, and any attack from a fake wouldn't injure Gravis, but that was never Jessy's intent.