In the distant past, villages were once being destroyed by monsters from the sea with unknown aims. Warriors and Refugees take to their boats in search of lands that were safe, where they could regather.
Elsewhere, people slowly stop acting like themselves. Children come home to find their parents whispering secrets. 6 months later, they vanish, leaving the child behind. In the next village over, it might be the children who vanish. Husbands and wives become distant. Friends become strangers. People abandon their loved ones and disappear.
There are not many safe, thriving places left out there. One of them is under attack. People are depending on you.