Thread:PeaVZ108/@comment-26888167-20180410034557/@comment-26888167-20180410043232

Because although that historical event was mostly kept as a secret, it became a legend for the crabs. When Captain Dark Shell was sealed, the crabs knew about it, and started to pass on the story from generation to generation. Other than the crabs, the only ones who knew about that event are the shadowfish. The Shadow Sensei probably knew about it too, but he's dead.