Chapter Text
It is a law irrevocably decreed across all of Olympus that the gods are absolutely, categorically not allowed to involve themselves in the lives of their demigod children. It's a song and a dance they are all well familiar with now. Meet a delightful new lover, play with the pretty toy for a little while, and be very careful to leave as soon as a child enters the picture.
The gods will tell themselves and their poor abandoned lovers as often as they like that it's for the child's sake. Demigods become stronger, braver, bolder when raised in harsher conditions. They are safer when kept away from the mythical world. If they do not know what they are, neither can the monsters around them that otherwise might sniff them out and attack. Of course, it isn't a foolproof plan. Trusting the safety of divine children to mortal parents is always risky. Some will do their best and raise a promising young hero. Some will find their charge too much and end up failing in some way, whether by intentionally giving up or by falling short at the crucial moment. Demigods die all the time. How can they have emotional attachments to their children, the gods would ask, if those children will inevitably die young? No, it is better for everyone involved that they remain distant.
Poseidon, God of the Sea, King of Atlantis, the Earthshaker, Stormbringer, Father of Horses, had never been good at heeding rules. The sea, as he would tell anyone who would listen, does not like to be restrained.
History would see Poseidon as many things. An avenger. A mighty destroyer. An impassable obstacle. Ruthless, cruel, impartial. One to be feared. One to be respected. One to be worshipped. But if there was one good quality Poseidon had, one thing that every myth agreed on, it was that he cared deeply about his children. It was his children he avenged, them he protected, them he loved. Perhaps Poseidon would not be considered a good person, but certainly if any of the major gods could be called a good parent, it was him.
The oath made between Zeus, Poseidon and Hades hung over the brothers' heads like a sword dangling from a fraying rope above them. The Great Prophecy weighed like the burden of Atlas upon each of their shoulders. It was a foolish endeavour, really. All the gods knew that the will of the Fates could not be avoided, even by the most powerful and fearsome among them. Nobody was surprised when it was Zeus, the youngest and most foolish brother, who broke the oath first.
Poseidon had visited his youngest niece only once, and even then he had only watched from a distance. She was maybe five years old, full of energy and life, so much like an innocent picture of her father in every measurable way that it was almost painful to watch. Would this innocent little babe one day be the downfall of the Age of the Gods? Would she lose her life at only sixteen to the cruel designs of a prophecy uttered decades before her birth?
It was such things Poseidon had been thinking about when Sally Jackson approached him on the beach in Montauk. He entertained her conversation only because she had asked about his "fork" (a trident, thank you very much, and wait, how can you see it?). He had no intention of taking a lover, no intention of giving little Thalia a baby cousin. There was just something about being with Sally Jackson that was… easy. Simple, perhaps. Like being around her made everything else feel insignificant. Sally herself? She was beautiful. In all his millennia of living, Poseidon had rarely seen such beauty among mortals. She spoke softly of dreams she had for a future where things worked out for her. She was unfailingly kind despite the harsh circumstances she found herself in, the destitution and loneliness that had been forced upon her. Poseidon was utterly captivated. The first time she had dared to take him by the hand, she had blushed hard and stared so intently at the ground that Poseidon had to take her by the chin and bring her face closer to his so he could kiss her. He would have done anything for her. He would have built a palace, made her a queen, and taken away all of her problems. And yet, Sally had too much integrity to accept, and Poseidon loved her too much to insist.
He was going to leave. Really, he was. He had stayed for as long as he needed to. If anything, Poseidon was sure he had overstayed his welcome by now. It was just… well, Sally was heavily pregnant. She couldn't move too well, and what sort of self-respecting man allows a pregnant woman to carry her own groceries? And surely she couldn't be expected to take herself to the store at 3 am to satisfy her random cravings, or to massage her own ankles when they became swollen and sore? And if he left, who would finish assembling the crib they had picked out together or finally paint the walls of the baby's room? It would be fine, Poseidon told himself. He would stay just a little longer. Just until his son was born.
Perseus Jackson came into the world screaming a battle cry. He was tiny and wet and ruddy-faced and so, so perfect.
"Strong one you've got there," the nurse commented innocently when handing Poseidon his tiny little son.
"Yes," Poseidon agreed, cradling his boy close to his chest and watching five tiny little fingers curling around his own. "A strong one indeed."
He was going to leave. For sure this time. Little Percy had been born, he had proved his existence to the world, and Poseidon was going to leave now. He would just take Sally and their son home first, of course. He had to make sure his baby boy made it into the crib he had put so much effort into. By the time they got home to Sally's little apartment, it was already late, and there was no point in leaving right now. He would surely just stay one night and leave in the morning. Sally needed the sleep anyway. Percy had not made things easy on her. When he woke up crying in the middle of the night, Poseidon had told his sweet lover to rest and that he would take care of the baby. He'd read the books - not because he planned to need the information, of course, it was strictly just out of curiosity - so he knew how to make the bottle just right, knew how to change the diaper without making too much mess, knew how to hold the baby and pat him just right to make him burp. Percy fell asleep safe and snug in his father's arms. Poseidon would leave when Percy woke up. Or he would leave when Sally had recovered enough to handle things on her own. He would definitely, for sure, leave before Percy was old enough to remember him.
Poseidon realised he was probably in too deep when he found himself sitting in the doorway of the bathroom, frantically scanning the book on potty training he'd bought (for Sally, not himself, of course) while his two-year-old son squatted over the potty asking loudly every twenty seconds or so if he had earned his blue M&M yet. He probably should have come to that realisation about a year ago when he and Sally had researched the most effective ways to raise a child to be bilingual so that Percy would grow up speaking Ancient Greek with his father. Well… there was still time, right? Percy might remember having a dad around at this age, but perhaps he could fake his death or something. Surely that would be fine. Poseidon really needed to leave.
Percy was four years old when he decided he was a shark, and somehow that was Poseidon's problem to deal with. He wasn't sure why; he was leaving any day now, after all. Still, Sally had decided that it was Poseidon's job to explain why biting other people is not nice, which naturally came with a long explanation of how sharks actually don't bite unprovoked, which in turn made Percy ask all kinds of questions about sharks that Poseidon couldn't help but answer, and eventually Sally had to come into Percy's room and remind Poseidon that bedtime was an hour ago. Most gods probably weren't doing a four-year-old's bedtime routine every night, but Percy simply wouldn't settle down to sleep without a story, and he absolutely insisted that Daddy told better stories than Mommy. Poseidon would leave as soon as Percy accepted Mommy's bedtime stories instead. Or when he was too old to need them at all anymore.
Percy's first day of school was emotional all around. Poseidon and Sally had held his hands and guided him inside, and he'd been very brave right up until the moment he realised his parents were about to leave without him. The ensuing meltdown had resulted in Poseidon crouching awkwardly in a kindergarten classroom for another thirty minutes after Sally had needed to leave for work (not that she needed to work - Poseidon could and would take care of everything, but she insisted that they at least split their expenses). By the time he'd reassured Percy again that he would definitely come back to pick him up at the end of the day, the great God of the Seas had almost been brought to tears himself (if he had a little cry to himself after finally escaping the building, that was nobody's business but his own). Clearly his little boy still needed him! He would simply have to leave once Percy could go to school without crying.
(The next morning, Percy had been perfectly happy to go to school without even looking back once. Poseidon told himself then that he would leave at the end of the week, just to make sure this wasn't a one-off.)
Three weeks later, the fridge in the Jackson household was adorned with the most incredible work of art Poseidon had ever laid eyes on. Percy had come home, proudly showing off the family portrait he'd made in crayon. On the left in dark blue was a vaguely humanoid figure with scribbles all over the lower half of the face (a wonderful abstract representation of Poseidon's beard. Truly, his son had a talent). On the right was another figure drawn in green with a big smile and long hair. In the middle between the two figures was a dark grey, vaguely fish-shaped figure with lots of sharp teeth.
"It's me as a shark," Percy said, pointing to this mysterious figure in the middle.
"Ah, of course. You make a wonderful shark."
"Yeah, but I'm a nice shark that doesn't bite people," Percy replied matter-of-factly.
"I'm very glad. Those teeth look sharp. I'm sure it would hurt a lot if you were biting people with them."
Sally came into the kitchen later that night when Percy was in bed to find Poseidon still admiring the portrait.
"He's growing up, isn't he?" she murmured, gently rubbing her hand up and down his back.
"He is. I should be leaving soon."
"Sweetheart, you've been 'leaving' for the last seven years. Percy will be devastated if you disappear on him now."
"Yes, I…" Poseidon trailed off, tracing one finger over the messy lettering that spelled out Percy's name in the boy's own uncertain handwriting. "I'll find a way to do it gently. Not yet, though, not while you're still working on your novel. I'll wait until you get your big break before I leave. Then I'll know that you'll be okay taking care of things without me."
Sally just hummed. "Alright, well, just let me know. Come to bed?"
"You know I don't need to sleep." Poseidon smiled at her, letting her take his hand in hers.
"No, but I do, and I sleep much better with you beside me."
"Alright," he acquiesced. "Just until I leave."
"Sure, whenever that's going to happen."
(Poseidon had no intention of leaving. They both knew it. They both ignored it.)