For Percy, soulmates had a deeper meaning than just a romantic partner. For him, a soulmate was a person who portrayed a deep and natural affinity towards him. A person who understood him inside-out. Someone who listened to him when he was going through a tough time, and showered him with unconditional love, whether it was platonic or romantic.

His first soulmate was his mother, Sally. The one who had sacrificed so much for him since the time he took his first breath, just so he could stay safe. She married an abusive man, for the mere reason of masking his scent from monsters. She went out of her way to colour the food they ate as blue because his stepfather refused to believe that blue food existed. She had sacrificed herself to the Minotaur and had fought alongside him as much as she could in his battles, figurative or literal. Sally was the reason Percy agreed to go to school and try to lead a normal life, despite his diurnal struggles. People may call him a "mama's boy", but he didn't care about their opinion. His mother would always hold a special place in his heart.

His next soulmate was Grover. He was his first best friend. His emotional support goat. Though they had to separate ways many times, he would forever remain his best friend at heart. They even had a complicated handshake and cheered each other up with terrible jokes and memories when the other felt down. They would share their losses and gains, sadness and happiness, tears and laughter. Their empathy link was the greatest symbol of their friendship. Despite its risky nature, Percy refused to break it, knowing that if either of the two died, the other would as well. And when he did die, how would never be able to reach Elysium and meet the others, for he would grow back as a plant or vegetation, just like a satyr. No matter the distance, their souls were intertwined in a complicated knot, refusing to break.

His third soulmate was his only true love, Annabeth Chase. If he were asked to describe their relationship through the years he would have never been able to find the right words. Best friend, crush, first and true love, girlfriend, fiancée or even wife didn't cover the intricate bond they had shared over the years. She was his better half, the light to his darkness, the peanut butter to his jelly. They completed each other in a way that even they never understood themselves. They were tied together by an indestructible thread; she was his mortal link to the world. Without her by his side, he had a lingering sense of emptiness. He felt as if he were drowning without her present as his anchor. If he had to, he would walk through hell again just to be with her. 

For Percy, Tyson was like an angel sent from heaven. He had been Percy's only friend during his seventh school and was now his little brother. Neither could bear to stand the thought of anyone hurting the other. The two were equally protective of each other and would jump in front of any danger just to save the other. There were times when the other had to go their way, but they would always find a way to communicate and catch up with each other.

He had found a soulmate in his little sister, Estelle. Though the only thing that came out of her mouth was giggles and drool, she had taken an instant liking towards his elder brother, and the brother-sister duo communicated through another language altogether, the language of love. Every time Estelle would hear Percy's name, she would giggle and flash the biggest, toothless smile as if she had just heard the best thing in the world. He was her inspiration for everything, despite her being just a baby. Percy would give up his life to protect her without hesitation. She was like a bright star to his dark sky, therefore fitting the meaning of her name.

Next came his stepdad. (No, not Gabe, Paul.) Unlike Gabe, he had a caring personality, and despite not being able to see through the Mist, he took everything about Percy's life in a fairly calm manner and supported him through every step. Though he may not be able to help him in his demigod life, he helped Percy in any way he could in his normal life, from homework tips to just fatherly love that Percy had never received before in his life; he did everything he could for his step-son. 

Then Percy met his friends from the Argo II. They were the only thing he had ever thanked Hera for. Jason, his friend, was his soulmate. Though he was no longer here, he would always remain the blonde, nerdy Jason with imperial gold glass frames, alive and breathing, in his heart. The moment they met, it was like something had clicked, and they immediately became friends. (not considering the time with the Eidolons). Piper and Leo were his partners in crime. They each had developed a sibling-like connection with Percy and were constantly known as the "prankster trio" upon the Argo II. Though he could have spent more time getting to know them, Frank and Hazel were some of his best friends whom he would lay down his life for. The link between the seven teenagers, who had bonded over a quest to put an earth goddess to slumber, had grown so strong it was almost indestructible. 

He had also found soulmates in his friends who had given up their life for the world and him. Beckendorf, Silena, Zoë, Bianca, Ethan, Luke, Castor, Lee, Michael, Jason and so many more. 

And finally, he had found soulmates in not only the campers of both camps but also some mortals like Rachel, titans, ex-titans, other mythological creatures, and even people from different pantheons. 

Once upon a time, a twelve-year-old boy, often regarded as the troublemaker wherever he went, only had his mother as his one true soulmate. Now, at age eighteen, as he sat smiling and staring at the sea ahead, he realised that his family had grown over the years. And no gift of immortality could have brought him this happiness of finding so many soulmates.