Below the Tide
This fanfic was requested by @JudgingTheNerdHaters
Persephone 'Percy' Jackson knew that war came with consequences, but she couldn't imagine this happening. All of her friends... dead. She still couldn't understand it, understand how. After the horrible war with Gaea, after the horrible massacre of demigods, Percy just didn't know what to do. Her father, Poseidon, only wanted what was best for her daughter and he could see how distraught she was. He saw how she wanted a escape. He saw how everything reminded her of ... them. He offered her a place in Atlantis, there she could start a new life, new friends, a brand new start. That is, if she wanted it, and she did.
Percy, being who she is, didn't want anything special, and she was given a normal place in Atlantis, that's all she wanted.
Of course Atlantis knew of the great hero who saved the world from Mother Earth, but the hero's name was kept secret.
During her time in Atlantis she met Kaldur'ahm, and boy, did they bond quickly. He was to only one in Atlantis who knew who she truly was, she has told him.
When Kaldur'ahm became Aqualad, he didn't leave Percy behind, no, he took her with him, and so she became Aquagirl. When the Young Justice team was formed, well, they both joined.