Ryuki sipped tea, and then he and Rena headed to school. Ryuki used his gift to understand some future events related to him, as well as Tanaka Ami, Sato Nana, and Yuta, about them related to yokai.
After many times asking in different ways, he understood that in the future, Ami and Nana would die. It was three years later.
His gift wasn't omnipotent; that could tell him anything he asked. The only reason he knew they died three years later was that he asked his gift how he could save Ami and Nana when he wasn't involved in their lives.
The answer was that he should tell Ami and Nana something three years later. The thing he had to tell them was that Yokai World was a trap that would destroy all the defense officers of the Yokai Department.
Moreover, he had a guess. Currently there were many people in the Defence Officers of Yokai Department, these officers lives life like a normal people but the they fell into a yokai trap three years later.