When he grasped the girl's hand, Sephiroth had a vision. But unlike Ashelia who had seen the destruction of Crystallis, Sephiroth saw nothing but darkness as far as the eye could see. He didn't see anything, but he could feel the madness that followed Ashelia's vision.

More than madness, the sensation was one of fear. This fear was born from a very simple fact-- The knowledge that he would die. Not the possibility of dying, but the realization that no matter what he did, no matter what any form of existence did, they would all die. Then the fear grew and became the fear to see everything dying, all of existence denied and returned to a void by the Calamity. The fear was inescapable-- If Sephiroth tried to accept it, the fear would still grow and if he tried to struggle against it or run away from it it, it would grow even faster.

But eventually; Sephiroth would come upon a realization: to overcome that fear, one would have to become the fear itself and then surpass it. After that, Sephiroth was kicked away from the vision and garden, only to be thrown into another memory. The fear and sensation would be all gone and he would remember it as if he had felt someone else's emotions-- But he would remember exactly how it had felt.