According to TV Line, Todd Lasance (The Vampire Diaries) has been cast as The Rival, as a recurring villain role for season 3 of The Flash.
Even though Lasance will be featured as a recurring villain, there’s no mention of his origin name. While he is originally Edward Clariss in the Golden Age comics and reappearance in the early 2000’s, during the Flashpoint story-line, he does take over the body of Golden Age speedster Max Mercury, which could hint at another twist for the audience, like we had in both previous seasons.
In the comics, The Rival is a Speedster akin to Reverse Flash from the Golden Age era, when Jay Garrick was the current version of The Flash. Edward Clariss becomes The Rival after hearing how The Flash gave his speed to another and being rejected when he presented his findings to the scientific community, his formula as he dubs Velocity 9, was shown in an earlier form in season 2 of The Flash as Velocity 6.
The Rival returned years later after Jay Garrick’s The Flash was established as being on Earth 2 where he becomes a member of the Injustice League, after the Justice Society of America is reformed.