One-line: king listening to the whole Purana because his father Parikshit died badly and revenge did not fix it.
First appears: Book 2, in Book 2 retelling.
Who they are: Janamejaya is the emotional reason the Devi Bhagavatam is being told. He is the son of Parikshit, the king killed by the snake Takshaka. Janamejaya first tries a snake sacrifice to destroy the serpent race, but that does not save Parikshit. So Janamejaya turns to Vyasa and receives the Goddess-centered Purana instead.
What they do that matters:
- Performs the snake sacrifice that Astika stops.
- Keeps asking Vyasa the questions that structure the books.
- Performs the Devi Yajna in Book 12 and finally frees Parikshit from hell.
Other names: None in this storybook layer.
Family / lineage (when relevant): Son of Parikshit; descendant of Arjuna and the Pandavas.