'The Blacklist' season 3 episode 21 spoilers: Katarina Rostova showing her face in 'Susan Hargrave'

Famke Janssen stars as Susan Hargrave in "The Blacklist" season 3 episode 21NBC

Famke Janssen gives a face to Red's worst nightmare in "The Blacklist" season 3, episode 21. The installment is titled "Susan Hargrave," which also happens to be the name of her "elegant, powerful and extremely dangerous" character.

Hargrave, who is nicknamed Scottie, was first shown in the final minutes of the tear-jerking episode 20 of the series, where she was photographed by Tom with Cynthia Panabaker, whose actions raise more eyebrows by the minute.

Liz's baby daddy believes that Scottie and Katarina Rostova are the same person. In "The Blacklist" season 3, episode 21 promo, Tom is determined to avenge the death of the mother of his unborn child. He is confident that Scottie is the person that put Liz in the casket.

In the next "The Blacklist" episode, Hargrave makes her presence more felt after Red attempts to foil her plans to kill more people following deadly events orchestrated by her.

During the episode, Red will catch up to her, making for an epic confrontation. Scottie is described as the "only person who can go toe to toe" with Red, which makes it more exciting to see what will happen during their hostile get-together.

Graced by each other's presence, Red tells Hargrave that she should be as dead as Liz by now. "Here's where we stand. Elizabeth Keen is dead, which means that you are too," Red advises Liz in "The Blacklist" season 3, episode 21 promo.

It has always been implied by Red that Katarina Rostova is the person that put dangerous people like Mr. Solomon on her daughter's own trail. On the show, it has always been suggested that a bigger entity is behind Liz's apparent death and that Katarina Rostova is a key player in it.

Not much is known about her yet but Liz's grandfather revealed in the previous episode of "The Blacklist" season 3 that she loved Liz enough to let her go, something Red can't even imagine doing.

"The Blacklist" season 3, episode 21 "Susan Hargrave" will air May 5 at 9 p.m. ET on NBC. The episode is expected to set the stage for a possible spinoff starring Janssen and Tom's essayer Ryan Eggold.