Kang, Zarrko, Superman, Cable, even the Flash and Green Lantern. Comics are full of beings who stroll through time as if it were a doorway. And maybe it is to them. Let’s look at one of the less celebrated time guys from the pre-New 52
In the year 2030, the world had been ruled by a villain named Monarch, who destroyed all of the Earth's superheroes. Matthew Ryder, a scientist, who remembered the time he was a child and was saved by a superhero from a collapsing building, decided to fight back at Monarch's dictatorship. Matthew discovered that Monarch may have been a former hero, so Matthew built a time machine (natch!) to travel back to the past to find out which hero would become Monarch.
Unlike previous test subjects who had died when they tried the time machine, Matthew survived. However, he was merged with the time stream and was given numerous powers, two of them being to travel through time at his own free will and to predict a person's future. With his new powers and appearance, Matthew took up the superhero name Waverider!
Making his way into the year 1991, Waverider predicted the futures of numerous heroes; however, none of them turned out to be Monarch. When Waverider accidentally came into contact with Captain Atom, the interaction of their powers resulted in a massive amount of temporal energy being unleashed. This created an opening in the quantum field which allowed Monarch, who had been monitoring Waverider's actions the whole time, to travel back in time to ensure his own existence. When Monarch later killed Dove, her partner Hawk became enraged and beat Monarch and unmasked him, only to see that Monarch was Hawk himself. (Shocker!)
Soon, Waverider and various heroes he gathered defeated a demonic being called Abraxis. Later, while Waverider was traveling through the time stream, he encountered himself as Matthew Ryder, who was from the year 2030, although Matthew was still a regular human and he had not become Waverider since Monarch's future reign had been erased.
Following this, the two of them joined the Linear Men, a group that contained time traveling beings who protected the time stream. Despite the Linear Men's policy of non-intervention in the timeline -- to the point that the previously actively interfering Waverider was discouraged from preventing Superman’s death during his first battle with Doomsday -- Waverider came to Superman's aid when he discovered that Doomsday had returned to life and was now working with the Cyborg Superman (soon to return in Supergirl).
Recognizing the danger of Doomsday's existence, Waverider showed Superman a detailed vision of the past to explain the circumstances of Doomsday's origin as a genetically engineered being capable of evolving to overcome anything that proved capable of killing him, as well as discovering that Doomsday's hatred of Superman was due to Doomsday's traumatic origins onKrypton leaving him with a deeply-rooted hatred of Kryptonians. The two heroes seemingly defeated the monster by taking him to the end of time, where the imprisoned Doomsday was destroyed by entropy (not to be confused with the Marvel entity) as the universe itself collapsed.
Later, during Zero Hour, Waverider was subsequently killed by Extant, who had evolved from Monarch. However, the human Matthew Ryder was still alive and was soon contacted by Metron, who told Matthew that he had to become Waverider and that he was the only one who could use time travel to save the universe. Matthew was then transformed into a new version of Waverider and took over the role his previous self did, helping a select group of heroes defeat Extant and Parallax’s effort to recreate time according to their own design by triggering their own Big Bang with the aid of Damage.
Junior and Georgia, two descendants of the villain Doctor Sivana (Shazam!), had rebuilt their father's sphere of Suspendium, which was able to let them travel in time. Although they were able to open a gateway in the past, they ultimately had to suspend their experiment. Right before shutting down the machine, they saw Waverider in the time stream, but failed to recognize him.
Later, Waverider was seen talking with the dying Time Commander, one of the former time traveling villains he tried to recruit in his efforts to save the timeline. Skeets, infected and controlled by Mister Mind, then arrived and killed the Time Commander. He then asked Waverider where and "when" Rip Hunter was in the time stream. When Waverider refused to tell, Skeets brutally tortured Waverider and later implied that he killed him and was wearing his skin.
Will a living Waverider make an appearance in the New 52? The opportunity is right – if not now, when?