Queen Harpy/Lucretia

''Every once in a while I can leave the village like this. It's nice to not have the responsibilities of a queen for a change, but I do feel a little guilty. Hmm, maybe I'll buy everyone a bunch of souvenirs for when I return to the village.''

What, you thought her name was actually Queen Harpy?

Recruitment
Advance the main story, till you reach Yggdrasil, the World Tree. Defeat the boss there, ask them for a seed, report to Grand Noah Queen, and return for your seed. Give it to Lucretia and she'll join you.