There are countless organizations in the universe, and one of them is their dream, called "Butterfly Tail".
"Butterfly Tail" only accepts strong people, and they only have one last name - "Oath of the Sea".
"Butterfly Tail" is very mysterious. No one knows how many there are, where they are, and how long they have been there, but there is no doubt about their power.
"Butterfly Tails" generally do not restrict their freedom. Most of them are distributed throughout the universe, doing what they like.
"Butterfly Tail" is an organization similar to a mercenary guild. They accept tasks from all over the world and have a 100% completion rate.
"Butterfly Tail" has the strongest team.
People with "Butterfly Tail" have almost eternal life.
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