Perseus Jackson had a unique birth. His mother, Sally Jackson, a daughter of Apollo, was so pure hearted and kind, all three of the sons of Kronos and Rhea fell for her. The fates put an enchantment on her so she could bare a son with the DNA of all three gods: Zeus, Poseidon, and Hades. When Sally died, they were all devastated, but although they wished it, they knew raising Perseus was not an option, for, it would only cause the infant pain to be raised by three brothers who more or less hated each other.
So the task went to Hestia, Aphrodite, and Artemis.
And thus begins the demigod life of Perseus Jackson, son of Zeus, Poseidon, Hades, Hestia, Aphrodite, and Artemis, grandson of Apollo, and the most powerful among god or mortal to ever live.