The Flash: 10 Best Villains (so Far)

The oh-so-arrogant Hartley Rathaway turned up in season one as a former member of S.T.A.R. Labs with a huge chip on his shoulder towards his ex-colleagues, particularly Wells. Imbued with an incredible increase in hearing thanks to the particle accelerator, Hartley turned his sights on destroying the Flash.

Though he only appeared in two episodes in the first season, watching his caustic interplay with Team Flash was entertaining, and the character himself earns credit for managing to outsmart Cisco and actually escape, avoiding capture from thereon out. I

n season two, however, Barry's meddling with the past saw him returning to the present only to find Hartley as a friend and ally to Team Flash, and it'll be interesting to see how the character's change in attitude plays out down the line.