Waverider

Waverider is Matthew Ryder from an altered timeline. In his own timeline Matthew lived under the rule of a dictator called the Monarch. Having been saved as a child by heroes Matthew became inspired by the superheroes of the past to fight back against Monarch. After discovering the villain used to be a hero Matthew built a time machine to travel back into the past to avert this timeline. Unlike other attempts by other travelers Matthew survived the ordeal. Although the process changed him by somehow merging him with the time streams' temporal energy. Physically changed Matthew dubbed himself Waverider. Eventually he came in contact with the Linear Men, who had just (depending on your linear POV) lost a member named Travis O'Connell. They asked Waverider to join their ranks.

Powers: Able to travel to any point in time by will. Waverider is also a seer that can see into a persons' future by touch alone. 

Waverider 2.0: In Zero Hour Waverider was killed by Extant, the evolved form of Monarch.Another Matthew Ryder was called upon to take on the role of Waverider in his place.

(Other) Deaths: During 52, time travelers were being hunted down by Mr. Mind and Waverider was unlucky enough to be discovered. Unable to reveal Rip Hunters' location (and boasting that Mind would never be able to outsmart Hunter) Waverider was murdered. According to the remaining Linear Men (New Earths' Matthew Ryder and Liri Lee), Rip Hunter argued with the group over Waveriders' paradoxical origins. They claim that he died during Infinite Crisis. How and why this differs from the events in 52 (which takes place during the year proceeding) are currently unknown.

First Appearance: Armageddon #1