Here's a proofread version of your text:
"Let's jump, NOW!"
Jim, with Cherry holding tight on his back, and Anya, jumped off the surface of the steep slope and into the green river below them. While falling, Cherry gained some energy and transformed so that her human bones would not break once she fell into the river.
Behind them was the raging Blood Bishop, Ace Underwood, who was in the middle of his evolution. In the middle of it, Ace had lost all senses of his humanity and saw his fellow Blood Mutants as potential targets to kill, hence the reason for him pursuing the others without giving up easily.
*SPLASH*
Jim, Cherry, and Anya fell into the river and got swept away by the rushing current. Ace, on the other hand, had lost sight of them, making him change his focus to the startled beasts by the river. Letting out a powerful roar, the Blood Mutant began killing and slaughtering the beasts, tainting the color of the river with the blood of his victims.
