They might also seek vengeance, sending minions to chase down and attack the party. After killing one hag they are now being chased by two more, creating a nice but manageable escalation of threat.
WotC showed off three high level monsters on D&D Beyond, recently, the Arch-Hag, Animal Lord, and Blob of Annihilation.
WotC revealed a partial stat block for the "apex fey" the Arch-Hag. Come take a look at what a CR 21 Fey packs in the Monster ...
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