I Have Zero Magic Power and You Want Me to Save the World?

50 Years later, he traveled from the future to the present. He had boundless magical power. Before he died, he predicted disaster to He Qing and taught her how to save the world. "You must unconditionally believe everything I say next, otherwise your family will die of strange diseases, this city will turn into purgatory, and the entire world will break out into a devastating war." While He Qing was hesitating, the tallest building in Yuezhou sank into the Lujiang River, and the whole country fell into turmoil. He is determined to follow the instructions of his future "self" and accomplish three things to prevent disaster from happening. A stranger with blue hair and blue eyes, a warrior with silver hair and red eyes, and a half-elf with blond hair and gold eyes. Even if his magic power is close to zero, with their help, he may be able to save the world. [Original fantasy, post-magic era background setting]