New Tales of the Old World - Evan A. Cushing

Chuck Evans, a man out of time, one of the last survivors from the Earth and other worlds, finds himself in a realm he no longer remembers. The monsters feared by the descendants of old Earth were made by Chuck's generation. Through ups and downs, and the discovery that he is no longer quite human, Chuck initiates a solution to save the world his people ruined. In the process, Chuck struggles with what he has become.