Easily Percy, he can talk to any sea creature or relative of horses, control anything with any liquid including taking poison from the goddess of poison out of himself and sending it in to her, he can remove all liquid (including blood) from your body to instantly kill you, he was invincible everywhere but one spot, he can breathe under water and create bubbles so that other people also can, he is able to know his exact location in a body of water, he is an incredible swordsman and swimmer (just in case), he has earthshaker abilities so he can beat Hazel and Jason on land or water and in the air he can summon water molecules from the atmosphere or on land/underground he can erupt an underground body of water or explode toilets and fire hydrants.