From the introduction:
The weight and crash of the water was your first home. There are times you miss it terribly, and raise your keening voice, and those that can hear are moved... closer. You have a removable pelt that you were born in beneath the waves. When you wear it, you look just like a seal. And when you remove it, you feel raw and beautiful.
You’re living on land now, far away from everything you’ve known; shocked by newness and possibility, burdened by longing
and the tyranny of choice. The air moves fast over you.
What do they call it? Ah, wind.
This is a playbook or "skin" (character sheet and basic play rules) for the Selkie character.