Siren: The Drowning
Siren: The Drowning is a fanmade game set in the New World of Darkness about mermaids.
You're a person who underwent the Drowning - a point in your life where you nearly gave into despair, only to come out the other side. You gained a Diluvian form, but you also gained knowledge of the Deluge - an apocalyptic event in the future that will wipe out humanity. Now you have to stop it, but there's one problem. You don't know who or what will cause the Deluge, or even what form it will take...