Truth is a precious commodity on The Blacklist, rarely available and devastating upon its reveal.

Tom Keen's Past Revealed On 'The Blacklist', 'Integral' Part Of Upcoming Episodes

'The Blacklist' Season 2 Spoilers: Tom Keen's Past Revealed, 'Integral' Part Of Upcoming Episodes

"The Major," however, provided viewers with the answer to a long gestating mystery - who is Tom Keen (Ryan Eggold). While the spy's life still has pockets of mystery, Red (James Spader) and the Major revealed Tom's dubious past, his true affiliations, and how exactly he came to know Mr. Reddington.

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Now, despite Red's dislike for the flippant criminal, Spader's character must track down the baddie in order to save Liz (Megan Boone) from the long arm of the law during the aptly tiled episode 16, "Tom Keen."

Unfortunately for Liz, she is still in the dark as to Tom's (aka Jacob) history. She only knows Tom as Berlin's henchman, and the truth would probably come in handy when Mr. Keen comes to help (hopefully) smooth over the investigation into the harbormaster's murder.

"She thinks of him as a very dangerous person now," Boone informed TV Guide. "Anytime he comes into her life from this point on is going to be an extraordinary circumstance -- whether he comes into her life seeking redemption.. or if he comes into her life to try and harm her again and try to manipulate her. She's going to be very skeptical. He's going to have reassure her faith in who he is."

Find out more about Tom Keen's turn as the blacklister of the week on March 19. See a promo below.

The Blacklist airs Thursdays at 9 p.m. ET on NBC.