Goddess Undone. Heaven Reborn.
A goddess long forgotten and on the verge of fading away, gets merged into a willing mortal girl's soul. She wants to see the world she has created and see how it has prospered since, if only for the last time before she disappears, perhaps for good.
She has seen the beauty of her creations and the devastating destruction her creations bring among themselves and the paradise she has so carefully constructed. Humans kill and plunder in their hypocrisy, and many innocent lives are always taken and lost at some point or another for power and gain. Exhausted, disgusted and disappointed watching at with what she created, she is about to leave when she notices a young man about to take his own life and plunge into the harbor. She saves him, but in doing so, uses up all the little power she had left. As she melts into water, she wishes the best for him and hopes humanity can still turn around and go in a better direction.
The young man survives but now awakes with an ability to turn himself into water. A fragment of the deity was left behind in him. And now the government sees him as a potential great weapon to use, and wants to experiment on him to see how exactly can he perform those actions and the mysterious source of that girl (when the deity saved him in the mortal body she possessed, it was in a metropolis city and people caught it on camera and video). So now there's a manhunt everywhere for the lad because they want to use and experiment on him.
Moreover, there's some crazy insane immortal who wishes to truly wipe all humans off the earth. That person has grown twisted and corrupted over time, losing himself to insanity as he watches humans repeat the cycle of destruction again and again and he tries but can never stop it; and has seen repeatedly the loss of loved ones and friends that hold dear to him.
For the young man whose life was viewed as insignificant and meaningless, now he's been placed into the prime spotlight with a very important role. He has to stop humanity from destroying itself ( government(s) ) and the twisted immortal who wants to wipe out all of mankind completely. But is he up for that task?