"The Flash" season 2 will reportedly introduce Doctor Light, but it isn't clear if the character will be a protagonist or a villain. However, according to a report from TVLine, showrunner Gabrielle Stanton clarified that the character to be seen in season 2 will be the female version, who in the comics is also known as astronomer Kimiyo Hoshi. 

Cisco (Carlos Valdes) and Caitlin (Danielle Panabaker) mentioned a Doctor Arthur Light in the backdoor episode for "The Flash" in the "Arrow" season 2 episode titled "The Man Under the Hood," but this was in reference to the male version of the character, a villainous ex-STAR Labs scientist.

It is possible that the male and female versions will have no relation to each other and that the male version was a mere Easter egg for comic book fanatics. However, in the "New 52" relaunch of DC Comics, it is heavily hinted that Kimiyo Hoshi is the wife of Arthur Light during the events of the "Trinity War" storyline. 

Kimiyo Hoshi aka Doctor Light is one of the most powerful superheroes in the DC comic universe, gaining her powers from the star Alpha Lyrae/ Vega. However, she is only prominent in DC storylines where the multiverse is involved such as the "Crisis on Infinite Earths" and "Infinite Crisis" storylines. 

Given how "The Flash" season 1 ended with a glimpse at the multiverse and season 2 has been confirmed to introduce this concept, Doctor Light may be one of the key characters that glue the pieces together. 

The CW network has not yet announced any official casting for Doctor Light at the time of writing. 

Season 2 will also introduce two new speedsters with Wally West (Keiynan Lonsdale) and Jay Garrick (Teddy Sears), as well as a new love interest for Barry (Grant Gustin) with the introduction of Patty Spivot (Shantel VanSanten). Tom Cavanagh is set to return as Harrison Wells, while the villain Zoom is also speculated to make an appearance. 

"The Flash" season 2 premieres this Oct. 6.