To the son of Hephaestus, he saw fire as a being, a bright crimson gilded deity that lived to destroy. Like the monsters Leo lived to destroy himself, inferno was the beast that made everything bow down before it and changes everything in an instant, taking away what you thought was flawless.
He supposed he can say the same for the sea. Despite the differences, they worked together in a familiar way; brutal beauty and destructive power.
He knew this just by looking at Pallas Jackson. Every time she moved her head, Leo had difficulty composing a final image for the daughter of Poseidon. In profile, her nose seemed sharp and her lips thin. At three-quarters, her cheeks were full and high, almost Asian. When looking directly at him, her teal eyes overwhelmed everything else. It seemed to him that, like the waves, her face shifted with the light, leaving nothing solid behind. Her dark curls were chopped short—evenly unlike Piper's jagged braids—so they bounced just shy from her shoulders. A swimmer's build, lithe and strong, she's tall, too, he noted as she and Annabeth hugged, noticing she was just about an inch or two to Annabeth's 5'7.
With most beautiful girls he spared a glance at—stared at, his mind corrected—he usually fell head over heels. Thalia was a good example of this, and some of the Campers. But this wasn't the case with Pallas. He knew in an instant this was someone he would risk his life for and she would do the same. The kind of sibling bond he was never allowed to experience. She had that kind of air around her when she reconciled with her best friend, and around the two people she was with earlier. Protectiveness. Familial love. Exactly like the little girl he saw back at Camp, poking around at the hearth's flames.
Leo could suppose that the whole 'opposites attract' quote now made sense to him. Fire and water, they were. But there were similarities that Pallas liked to pick out whenever he brought this little fact up; unrestrained, preternatural, alive.
They brought what couldn't possibly be allies together. Just by the mere act of them forming a special kind of sibling bond, they combined the water and fire.
Watching as the flames streaked above him and the sea churn below him, they became as he became. The rest of their destiny was scorched into them, branding heart and soul.