Nico's twin sister

So I don't know if anyone has made a story like this, but here we go. Anyway none of the characters are mine they belong to Rick Riordan, the only characters that are mine are Nova Di Angelo, Cherry Blossom, and Rip Tide.
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This prophecy probably isn't perfect, but I hope you enjoy it and I'll try and get the other stories done soon.
Oh, really quickly so this sign ~like this means it's a video~ and if its like (In bold)~This it's what there thinking~ hope that helps onto the story.
-Three went in.
-Three came out.
-Two found Salvation until one had passed.
-The other was sent away.
-Now he who lives, shall find the lost one.
-She was taken by the shadows of darkness
-Only he can bring her back