The Flash has added a Heroes alum to the roster for Season 6, but there's nothing heroic about this new guy.

Showrunner Eric Wallace announced Saturday during The Flash's San Diego Comic-Con panel that Sendhil Ramamurthy will join the show this year as a toe-curling new villain. Ramammurthy will play DC villain Bloodwork, also known as Dr. Ramsey Rosso. He's described as "a brilliant physician with a genius intellect, and the world's leading expert on hematological oncology."

We also know he's a former colleague of Caitlin (Danielle Panabaker), who will come back into her life after an unexpected event throws them together. Unfortunately, this guy has "evil scientist" written all over him, and their friendship comes to an abrupt halt when his work transforms him into the monstrous Bloodwork. Canonically, Bloodwork's abilities include invulnerability and the power to control blood, and if that's what we're getting from this new guy in Season 6, this could turn out to be a pretty creep-tastic new season.

Sendhil Ramamurthy,<em> The Flash</em>Sendhil Ramamurthy, The Flash

This wasn't the only Arrowverse casting news of the day though!

Arrow showrunner Marc Guggenheim revealed that they've cast Charlie Barnett as John Diggle Jr. in the flash-forward storyline, and he'll be joining the show as a series regular. Unfortunately, it doesn't sound like J.J. will be following in his father's noble footsteps since we'll meet him as the leader of the Deathstroke Gang, where he'll face off with Mia (Katherine McNamara) and Connor Hawke (Joseph David Jones).

Discover Your New Favorite Show: Watch This Now!

On the Supergirl side of things, we'll have two new faces to greet when the show returns for Season 5. Julie Gonzalo has been cast as Andrea Rojas (aka Acrata), a "polished businesswoman and heir to a Central American tech empire," who will be making waves in the media industry in Season 5. Canonically, Acrata has a mysterious ability to teleport whenever in the shadows. Staz Nair has also been cast as William Dey, a renowned reporter who will no doubt cross paths with Kara (Melissa Benoist). Unlike Andrea Rojas, William Dey is an original Supergirl character, and all we know about him is he'll be somewhat cynical and look down on Kara's earnest idealism.

(Disclosure: TV Guide is owned by CBS Interactive, a division of CBS Corporation.)