Birka

Birka was a sky island far to the southeast from Skypiea. It is only ever mentioned in the series.

Enel was born and raised on this island, but six years ago after finding and eating the Goro Goro no Mi he destroyed his homeland and came to Skypiea with his followers.

Birka was said to be home to many strong warriors, powerless before Enel, however. Though it was his original home, Enel did not show any sign of love towards it, as he destroyed it without any hesitation.

The island shares its name with an ancient city on the Moon.

Trivia

 * The island and ancient lunar city may have been named after Birka, a Viking-age trading center in Sweden.