Fin
Proteus and Percy raced towards the direction of the conch, back to Triton's castle. As the approached the region's boundaries the water was ice cold. Usually as one swam towards the castle the water around got brighter and warmer but the water grew darker the closer they got. When they finally reached the castle they saw what was blocking out the light, monsters as black as night swarming the castle, creatures from the deep like they've never seen. Mermen soldiers were fighting valiantly but to know avail. They scanned the waters for looking for Triton, where could he be and more importantly where was Poseidon?
Proteus shouted, "In the name of Tethys" his battle cry shook the water all around and with that order the men that had followed him engaged in battle to help relieve the castle of these creatures. Proteus' men carved a path in for he and Percy. Percy shouted over the battle, "My guess is to head to the arena, it'd be the smartest place to hold out and engage these creatures or whatever else may be here."
As they swam for the underwater coliseum they could make out they approached the coliseum they could see more creatures in the distance, an army of Oceanides, Sea Nymphs, sirens, gorgons and behind them a creature Percy was already familiar with, Cetus. Then Triton swam up and said, "I've been searching for father but I cannot find him, surely he would not abandon us?" Proteus exclaimed, "Regardless we will need more help between my allies and your tritones this aren't going to be enough."
Oceanus laughed as he watched the creatures of the trench along with his own children ravage the Olympian ruled sea-world. Mariana was dazed and confused from what she saw. "You said we needed these allies for protection, not to formulate an attack." Oceanus retorted, "If we don't attack first then they will, it has always been their nature. I watched my siblings fall at their hand during the Titanomachy." Mariana knew something was amiss here and was starting to regret much fast. "What if I am on the wrong side of this , what if I have trusted too quickly, what if Oceanus' kindness has blinded me?" She heard a warm voice fill the water around her, deep and soothing, "Listen to your heart young sea goddess."
Out of the dark blue waters poured more creatures from the trench, the things of nightmares. Percy unsheathed Riptide and saddled Rainbow and went straight for Cetus who was tearing through Mermen and Tritones. As his blade met scales he didn't know how they could ever win this war, it seemed as though the enemy had an endless supply of reinforcements lurching out of the trench and they were vastly out numbered.
Percy felt a warm current pass him and remembered the last tie he felt the same calming waters near the Azores. Then from the east came Nereus with an army of Nereids and backing them, the sea monster Scylla. The Nereids clashed head to to head with the Oceanides and sea nymphs while Scylla hurdled for Cetus. That warm voice called upon "Tanagran Tritones" an ancient breed of sea-monster which met the the sirens and gorgons in the battle.
With Nereus' forces and Pontus' blessing they might actually overcome the forces of the trench.
Oceanus had one last play, he beckoned Mariana to unleash the full extent of her power onto this pitiful opposing army. "Mariana you can end this now will the creatures of the deep to launch one more full all out attack and the seas are ours." Mariana knowing she did not want to rule the sea but instead be in the light did the exact opposite. She halted her monsters and called them back to the trench. "Win your own battle, I may be born of night and darkness but I do not wish to be its creator." With that she attacked Oceanus an epic battle that all could see as the trench monsters retreated and Oceanus' forces became outnumbered. Oceanus pinned Mariana and slashed through the water with his blade to inflict a fatal blow but was not met by her flesh and instead was met with gold. He looked up to sea the golden Triton in the hands of the god Poseidon who had parried his attack on Mariana.
Author's Note: So I messed up and confused myself when I said Pontus and Oceanus were the same because they are not. I made my villain one of my helpers... so I went back and changed the previous story to work with this one and the introduction story. I found from this family tree that what I had thought about them being one and the same was not the case. My mistake!
So let's get into this story, the underwater place is most likely something similar to Atlantis. In greek myth it never really talks about where Poseidon lives or what it looks like we just know it's somewhere in the Mediterranean. Now for the sea creatures that are part of Oceanus army, they are all descendants of him and Cetus added in for fun. I thought it would be cool to have to legendary sea monsters Cetus and Scylla duke it out. Scylla was a creature with twelve dangling feet, six long necks, and heads lined with a triple row of sharp teeth. In the other corner, Cetus was a serpentine fish with long rows of sharp teeth. Fun fact they were both children of Keto and Phorcys. Nereus is another sea god, the son of Pontus and the father of Amphitrite Poseidon's wife. Nereus daughters are sea nymphs called nereids. Now I know you haven't heard of this one Tanagran Tritones which are ancient sea creatures not to be confused with Tritones (the children of Triton).
In the battle that took place I wanted a more even clash of monsters, I wanted the two armies to be on even playing fields.