[s4e8] Requiem -

: This detailed article from Pop Culture References explores how the episode serves as a major clue to Reddington's true identity, showing Kathryn's life as Liz's nanny and her initial bond with Katarina.

: Titled "Gold, Glory & Custer: Requiem Part II," this episode is praised by history buffs for its authentic use of Lakota dialogue and historical figures like Chief Touch the Clouds. [S4E8] Requiem

(Season 4, Episode 17 / Often cited as S4E8 in specific contexts) : This detailed article from Pop Culture References

: For a broader look at the secrets revealed during this era of the show, the Raymond Reddington Wikipedia page summarizes the "imposter" theory and the role Kathryn played in hiding the truth. Glory & Custer: Requiem Part II