A new Prophecy (BOO Spoilers, read at own risk!)

Percy Jackson sliced a head off another wooden post. Slash, dodge, stab, slash, dodge, stab, Went his trusty bronze sword, riptide, as it cut through the straw dummies on posts at the practice arena at camp. It was July 3rd, and said 20-year-old demigod was hot, sweaty, tired, and hungry, but it was only twenty minutes into afternoon free period at camp half-blood. He still had 10 minutes to go, so he splashed some cold water on his face and kept beating up the dummies. 10 minutes later a conch horn sounded. Lunch Time! ,Thought percy as he recapped his sword, turning it back into a pen, and allowed himself to become dry, sense he no longer needed the energy from the water. He ran off towards the dining pavilion. He was just sitting down at his table when he heard a petrifying scream from the lake. Nereids! Conversation stopped. Chiron motioned for Percy to come with him to the lake, just in case it was some problem with the water. It was not, however, a problem with the water, unless, of course, you count twelve year old girls with one shoe, a sharp pencil, and choppy black hair, swimming for her life from an invisible force, a problem with the water, because that was exactly what Chiron and Percy saw. They helped her out of the water, where she sat on the edge of the lake, breathing heavily, staring at the lake as though she expected a figure to appear there. She must be a demigod, thought Percy, otherwise she couldn’t have gotten through the barrier. “What is your name, child?”, asked Chiron. “Um...I’m Nereida Sardo. What...What was that thing?”, replied the girl. “what thing?” , questioned percy, “tell me how you got here.”. “There was a...THING in the water. It chased me. One minute I was just swimming around at my family’s lake house, the next thing I know, this fish-only it had a horses head and was the size of a rowboat-was chasing me. I swam for my life, but it got my shoe. At that point, I tried to stab it with my pencil, but it got my hair, see?”, she asked, pointing to her choppy, shoulder-length hair. Percy glanced at chiron, having a sort of silent conversation: Hippocami? Usually they aren’t that vicious!
Which god do you think she’s a child of? (that was chiron)
Umm...Guess we’ll just have wait and see. (percy again)
Percy, Do you mind showing her around camp and getting her a weapon (with assistance from Annabeth,) after dinner?
Sure!

The centaur and Percy led Nereida back to the dining pavillion, where the were met by hundreds of staring eyes. Percy sat down at the poseidon table like before, and Chiron led Nereida to the front table, where they introduced Nereida and sent her to the new “UNCLAIMED” table, where all the unclaimed children sat. From there on out, dinner continued as usual. After words, as promised to Chiron, Percy took Nereida aside to show her around camp. “So”, he started. “This is the dining pavilion.” Umm..It’s where we eat our meals, obviously”. And so he led her around camp, showing her the archery range, where she proved to be a very good archer, the Forges, the amphitheater, where she became very excited for campfires after being told about the enchanted flame and the Apollo cabin’s music, the cabins, where Percy explained about how every demigod had a godly parent and answering her questions about demigod life, the strawberry fields, where Nereida was very shocked to see the satyrs, having not been told about them and their legs, and the armory, where, along with some help from Annabeth, selected an enchanted Bow and arrow, with infinity number of arrows and the ability to turn into a binder clip, which she clipped onto her belt loop, along with a imperial gold dagger with the ancient greek word, “διάρκεια ζωής του δίσκου”, meaning “life blade”, carved on the hilt. Then, Percy remembered one site that he had not shown Nereida: the pegasi stables. He led her across camp to the collection of wooden stalls that housed the pegasi. He introduced them one by one: Guido, Porkpie, Silvia, George, Lite, Astera, Yolo (Connor and Travis Stoll’s Pegasi), Atlanta, Elysium, and finally, Blackjack. When they reached Blackjack, Nereida let out a little scream. “What is it?, Percy inquired. “Nothing”, she replied. “You’d think I’m crazy if I told you.”. “Honestly, nothing could surprise me at the moment,”, Percy told her. “Ok...Umm...I can kinda hear your Pegasus. He said, “YO, What up, captain?”. Yeah, go ahead call me crazy”, she said. Percy Stared at her, and she looked down at her feet, ashamed of her ‘craziness’. But Percy was no longer staring at her face, he was looking above her head, where a green orb floated, the same one that had appeared above his head the night he had been claimed as Poseidon’s son...

Notes

What will happen now? Who is the second child of Zeus?