The finale of The CW's third season of "Supergirl" inches closer, with only two episodes to go.

The upcoming episode 12, titled "For Good" focuses on increasing tensions between rivals Morgan Edge (Adrian Pasdar) and Lena Luthor (Katie McGrath). An assassination attempt on Edge leads him to believe Luthor is responsible for it and promises revenge. Luthor, who is afraid that her hatred and manipulation will pull her into the dark side of the Luthor lineage, then becomes a victim of an assassination attempt on her own life. Kara Danvers (Melissa Benoist), Supergirl's human alter-ego, manages to save her in time.

Meanwhile, Samantha Arias (Odette Annable), who is still unaware of her mental blackouts as the world killer Reign, seeks help from a friend, Alex Danvers (Chyler Leigh), about her memory loss and blackouts. The doctor, and Supergirl's sister from her adoptive family, Alex, agrees to help and performs a series of medical tests on her.

According to a report from Entertainment Weekly, episode 13, the season finale, will introduce a new villain in preparation for a new arc for next season. This new villain takes the form of Purity, another Worldkiller, played by "This Is Us" actress Krys Marshall. The DEO captures the new Worldkiller, as Supergirl and Alex try to interrogate Purity for information on how to defeat Worldkillers. However, Purity escapes confinement and rampages through the city subways.

In the previous episode, "Fort Rozz" revealed that Reign is a Worldkiller from Krypton, and that there are others out there like her. Although not yet revealed in the TV show, Worldkillers are well-known in the comic books. They are killing machines created by a Kryptonian science team. Reign herself was created by none other than Zor-el, Supergirl's own father. It is not yet known if this is the path the TV series will take.

"Supergirl" will air for two more episodes this season on Mondays at 8 p.m. EST on The CW.