Why did they kill off Elizabeth Keen on Blacklist?

Elizabeth Keen was killed off in "The Blacklist" to create a dramatic shift in the show's narrative and to deepen the emotional stakes for other characters, particularly Raymond Reddington. The decision aimed to reinvigorate the series by exploring new storylines and character dynamics, as Keen's character had become central to the plot. Additionally, the creative team wanted to take the show in a different direction, making way for fresh developments and challenges.