4. "Maiden Mother Crone" (episode 9)
The finale of Agatha All Along, "Maiden Mother Crone" was actually released as the second part of a double-episode finale drop, landing on Disney Plus with the eighth installment, too. Even so, this is the ninth and final episode of the season, so it's technically the actual finale.
It's definitely an unexpected kind of finale as it comes after the majority of the storylines have already been wrapped up at this point, but that allows it to take a trip into the past to help us get to know a bit more about Agatha Harkness herself. But it also serves a major purpose to the present, as it is revealed that The Ballad of the Witches' Road is a con that Agatha came up with after singing the song with her son Nicholas - a con designed to lure witches to their deaths by provoking them into blasting her. That is, until the door actually appeared when she sang the song with her most recent coven (thanks to Billy's limitless powers).
Ironically, while all of the other characters in her coven got episodes focused on them and their backstories, it was Agatha who didn't. Her trial was the shortest episode of the season and it didn't really focus on her motivations in the way that the others' did. So it's quite fitting that the show gets to bow with an hour focused solely on the protagonist herself. And among its many accomplishments, it showed us once again what a complicated character she is.
Seeing her happy with her son by her side made Nicholas' eventual death all the more tragic and painful. That's why the episode's conclusion, in which she decides to remain a ghost to guide Billy because she's not ready to face Nicholas in the afterlife, is extremely poignant. Understandable, but poignant.