How does captain morgan know all this?
There are many questions about the "vessels": How are they chosen, how can multiple people control one body, where the physical body goes etc.
The one I have the most difficulty fanwanking an answer to is how does captain morgan know everything he does aka who wrote the book? How does he know the very specific details of when a vessel becomes ripe and what happens if you're late?
I guess we could just say: "It's a magic portal, so there's magically also a book explaining everything". But that seems unsatisfying.