When Supergirl returns next month for its Season 3 premiere, titled "Girl of Steel," Kara's efforts to cope with the loss of Mon-El will be interrupted by someone who takes an immediate interest in her.
According to the newly released episode synopsis, this character has "a mysterious connection" to Kara. We know this figure isn't Odette Annable's Reign, whose brief appearance in the Season 2 finale revealed her ties to Krypton, but rather a citizen of National City. That would seem to point in the direction of the villain Bloodsport, who was teased in the latest Season 3 promo.
In the comics, Bloodsport was a firearms expert with an extensive line of high-tech guns, some of which fired Kryptonite bullets. Created by John Byrne, the character first appeared in 1987 in Superman Vol. 2 #4. A product of the time, Bloodsport was obsessed with the Vietnam War after his brother returned from the conflict grievously wounded. Lex Luther preyed on his weakened mental state to convince him to hunt down Superman.
Screen Rant reported in July that casting was under way for the role of Bloodsport, depicted as mercenary who breaks into his former base and steals equipment necessary to cloak an underwater nuclear device.
Here's official synopsis for "Girl of Steel":
DREAM A LITTLE DREAM OF YOU — Kara (Melissa Benoist) deals with the loss of Mon-El (Chris Wood) by focusing all her energy on being Supergirl and the mysterious new threat against National City. Alex (Chyler Leigh) confesses a secret to Maggie (guest star Floriana Lima) about their impending nuptials. A citizen of National City has a mysterious connection to Kara, and Lena (Katie McGrath) makes a bold move. Jesse Warn directed the episode with story by Andrew Kreisberg and teleplay by Robert Rovner and Caitlin Parrish (#301). Original airdate 10/9/2017.
Returning to the CW on Oct. 9, Supergirl stars Melissa Benoist, Mehcad Brooks, Chyler Leigh, Jeremy Jordan, David Harewood, Calista Flockhart, Chris Wood and Floriana Lima.