A Sailor's Power

In a world where the seas are covered with pirates, there were sailors who formed an alliance within a Crater, thinking they were safe from them. Though, they weren't alone in the Crater; surrounding their perfect island were other islands filled with mythical creatures. Those creatures keep to themselves as the sailors did the same. Soon the two were benevolent without any hostility in the beginning.
Although, that peace between them didn't last long. Over the years--- centuries specifically, sailors begin shifting into cruel, foul beings, only caring about themselves. Those creatures were only seen as rewards and low lives as they were no match for their power.
Shortly, creatures were fighting to defend their kind.

At the start of a new era, three characters were brought into this world. At a young age, they thought they were becoming like the older sailors they once admired. Instead, the truth passes their eyes, making them see what their home is really like.
Sliding with a foul creature from the seas, Mabel, Pacifica and Dipper are off with allies by their sides to defeat the wicked in their home. As well as ending the long-ending war with the mythical creatures.
However, will any of them survive against the wicked leader and his pawns?

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Warning: There will be some themes shown in this story, so be careful reading at your own pace! ^^
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The cover picture was created by me.
Any Gravity Falls characters that appear in this story do not belong to me, they rightfully belong to Alex Hirsch.
Any made up characters I created belong to me.