Your mother, Sally Jackson, had you, she was a single mother and they did everything together but then she met that man, he was nice and respectful to her and you. What you didn't know is that that man was the God Poseidon.

Your mother became pregnant with him and for her, yours and your brother's safety he left.

Your brother Percy was a demigod and you always noticed that your mother was more attentive to him for that reason.