Talk to someone ... on a ghostship ...
I talk with someone on a ghostship,but nothing happened
What should i do？
You need to advance relationship with the Demoness. Once you get that relationship far enough, you'll be able to bring Liam onto the ghostship, which... I don't understand why that matters, but it unlocks the next step (which is to talk to someone else who was already on the ghostship but wouldn't do anything before).
...then, when you meet all requirements and talk to the right person, the game gets stuck in an infinite loop. I haven't found a workaround yet.