Warning: The following contains SPOILERS for The Flash season 8, episode 18.
A new theory suggests that the version of Eobard Thawne introduced during The Flash season 8 came from a time in the past — from before he became the Reverse-Flash. The history of Eobard Thawne is difficult to map, given his extensive travels through time, space, alternate realities, and alternate timelines. This means there are several explanations for how an amnesiac and seemingly reformed Eobard Thawne might have come to exist in Central City in 2022, despite his having apparently been killed several times and erased from existence.
In the original The Flash comics, Thawne was a Flash fanboy from the future who traveled back in time to meet his idol after replicating the circumstances that gave him superspeed. After emerging in the Flash Museum and admiring the exhibits, Thawne discovered, to his horror, that he was destined to become the worst enemy of the hero he'd worshipped all his life. This knowledge drove Thawne mad, driving him to dedicate himself to replacing his former hero, or destroying him so that he could get his life back.
Related: Reverse-Flash's Return Risks Repeating Barry Allen's Oldest Mistake
The exact reasons why the Arrowverse version of Eobard Thawne (Tom Cavanagh) hates Barry Allen have never been revealed, although he has tried to kill him and replace him several times. Their most recent battle came during the Armageddon event that opens The Flash season 8, where Thawne attempted to trade places with Barry Allen in analternate future timeline he dubbed the Reverse-Flashpoint. This version of Thawne, who had taken on the appearance of scientist Harrison Wells, was depowered and locked away in a secure ARGUS facility
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