My Water Element Clone

"The task of saving the future of mankind is left to you." The old man patted his shoulder and said seriously. He nodded heavily, then turned around resolutely. He wants to go back in time, change the drought, and save the world. Later, he could transform into water and had a strange system called the Water Realm. His name is Xie Cheng, he is a water man, and he is the strongest repairman ever!