Professor Eobard Thawne (born c. 2151), also known as the Reverse-Flash, is a meta-human speedster from the twenty-second century, a descendant of the late Eddie Thawne, a time criminal, and the archenemy of Barry Allen/The Flash. Obsessed with the twenty-first century's Flash, Eobard recreated the accident that gave the Flash his powers and became a speedster himself. But after his very first trip back in time, Eobard learned that he was destined to become the Flash's archenemy and grew to despise the hero, attempting to prove his superiority as the Reverse-Flash and therefore became the opposite of his former idol. Since then, the two speedsters battled each other for many years, but neither of them were strong or fast enough to defeat each other.
After learning the Flash's secret identity, Eobard traveled back in time to kill Barry as a child to erase his foe from existence but was thwarted by the Flash of a later time who brought the younger Barry to safety. An enraged Eobard then killed Nora Allen and framed Henry Allen for the crime instead. However, Eobard lost his connection to the Speed Force, becoming trapped in the early twenty-first century. Realizing Barry was the only way to return to his time, Eobard killed Dr. Harrison Wells, the director of S.T.A.R. Labs, and assumed his identity to push through for the creation of a particle accelerator to ensure that Barry would become the Flash. Posing as Wells, Eobard mentored the Flash and became the leader of a team he assembled to stop the meta-human threats, to increase his protégé's speed so that Eobard could use the hero's connection to the Speed Force to return to his own time. After his plan was exposed and subsequently foiled, he was erased from existence after Eddie killed himself to stop him.
One year after Thawne was erased from existence, Barry prevented Eobard from murdering Nora, creating Flashpoint and held captive for months. After realizing this mistake, Barry released Eobard, allowing him to kill Nora. As a result of being pulled out of the timeline, Eobard was spared from his fate and continued to exist as a time remnant, while his original actions remain intact. Due to his own nullified state of existence being an aberration, he was hunted by the Black Flash, forcing him to seek out the Spear of Destiny in order to restore his natural existence. Unable to find the object and outrun the enforcer at the same time, Eobard formed a supervillain alliance. Eobard and his co-conspirators eventually retrieve the Spear of Destiny, which they use to rewrite reality to their whims. Despite initially succeeding, his plan was foiled by the Legends de-powering the object, and Eobard was vaporized by the Black Flash.
Despite his erasure from existence, Eobard's time remnants are preserved throughout history by the Speed Force, keeping his past time travels intact in order to stabilize the timeline (where his manipulations of it span several years) and prevent further paradoxes.
Later, Eobard mysteriously resurfaced as an ally of the New Reichsmen of Earth-X. He originally tried to carry out the Fuhrer's request to perform heart surgery on Overgirl. However when the Reichsmen's defeat eventually became inevitable, he abandoned his allies to their deaths at the hands of the Earth One heroes and Supergirl, running off to parts unknown.