During Wednesday's midseason finale, star Ryan Eggold's Tom Keen was shockingly killed off the NBC procedural. And unlike other "deaths" during the drama from creator/ showrunner Jon Bokenkamp.. Keen died during the midseason finale after being attacked by Ian Garvey, the season's main antagonist. He is still dead, but appeared as a figment of his wife Elizabeth Keen's (Megan Boone) imagination.
Tom Keen's death was the root of Liz's quest for revenge. That's the reason why she became so toxic and trust no one, and ruin some things, and mess up with the people that really care.. It is eventually revealed that the real Raymond Reddington died, likely at the hands of a young Elizabeth during a violent confrontation involving her mother. The imposter assumed Reddington's identity thereafter.