The tale of twin tyrants named Tempus show how time, and one's perception of it, can shape one's life. On Earth-One, a criminal named Tempus inspired toward villany when he felt slighted over a prized clock he perceived ruined by Superman. Using his skills as a clockmaster he created his Doom Clock which could cause disasters the coincided with previous cataclysms, he found his greatest foe was Superman's pal Jimmy Olsen. After outsmarting him after three vile attempts, Tempus returned later using clones of Olsen possessing superpowers Jimmy previously poseesed. Once more, Jimmy won the day.
On Earth-Two, or rather within its timestream, an unspecified man also named Tempus had himself gained the knowledge to access time, using it to create duplicates of himself and prevent travelers throughout the timestream from venturing forward. In fact, it was this Tempus who had prevented Per Degaton from voyaging forward through time, causing a time barrier in much the same manner that the Time Trapper on Earth-One had erected to unsnare his enemies the Legion of Super-Heroes. After an encounter with the Flashs of two Earths, following their pursuit of Vandal Savage's immortality comet, Tempus allowed the Scarlet Speedsters to return to Earth-Two to face their foe.