The Flash: 10 most disliked characters, ranked
2. Chillblaine
If there was ever a character on a major TV show that did not need to be a series regular, it's Chillblaine on The Flash season 9. The character debuted in a recurring capacity in season 7, forming a relationship with Frost, but he didn't have much to do beyond being her partner or getting in Team Flash's way. When the show bafflingly killed Frost off, it decided to make the equally baffling decision to promote Chillblaine to a regular character.
Actor Jon Cor played the role just right, getting that balance between campy villain and reformed bad guy spot on. On occasion, even the material served him well as the beginnings of a redemption arc for the character looked like it might pay off after Frost's demise. But the final season completely negated that, as a once serious storyline about grief was swapped out so that Team Flash's newest member could turn on them (again!) and join the Rogues. Meanwhile Barry told everyone (and the audience) that they shouldn't give up on him, when he had done nothing to prove himself worthy of being saved. Two episodes later, it all played out predictably and he made up for his mistakes... only to disappear off-screen after being temporarily written out of the show.
Chillblaine constantly shifted from pointless to infuriating on the turn of a dime, so audiences had already grown tired of him before he was a main character in season 9. The arc he was given in that final season, however, doubled down on all of those problems as the show just abandoned any hope it had of giving him a remotely nuanced story.