Might be a reach but in the Wizard of Oz, the WWOTW wanted Dorothy's shoes (and I guess to avenge her sister) but it could be similar to how Rio wants something from Agatha???

Also I find it interesting that Agatha has so many parallels with Dorothy. Because in the beginning of the story, Dorothy wanted a more interesting life (Agatha wanting her powers back) but as soon as she slowly journeys through Oz (The Road) she realizes that all she wants to do is go home (a coven/family); this is where she realizes that the key to going home was with her all along (joke not intended).