Leo is the character who gets a story most like the actual Greek myths. His flashbacks to his childhood with Tía Callida are odd and wrong and disturbing in a way that has more to do with weird, scary Greek myths than with the videogame world of the rest of the book where challenge can be overcome with smarts and the right tools. Callida puts him in a fire when he is two; she gives him knives to play with when he's three; when he's four, she tries to get him to poke a rattle-snake. The descriptions of these encounters are particularly fine, and show some of the best writing in the book:
He remembered resting comfortably, grabbing at sparks like fireflies. He dozed, and dreamed of a boat made of fire, sailing through the cinders. He imagined himself on board, navigating the sky. Somewhere nearby, Tía Callida sat in her rocking chair—creak, creak, creak—and sang a lullaby…
Leo remembered looking over his mother's shoulder at the flames curling around his blankets. Only years later had he realized he'd been sleeping in a blazing fireplace. (11.9)
Though this is meant to have actually happened, it feels like a dream—especially compared to the mundane visions in most of the rest of the story (check out our bit on sleep in the "Symbolism, Imagery, Allegory" section). Leo notes that Tía was never "banished from the house" (11.10); she showed up again and again. Did his mother know that Callida was really the goddess Hera? Or was it only Leo who saw her or knew she was the same person? Would Hera have let him die if the rattlesnake bit him? We don't know exactly what's going on, or why.
This is also the case for the creepy scene where Gaea comes to Leo. Gaea herself, threatening him with her eyes closed, seems to come out of a horror film dream: "She moved more like an avalanche than a person—a dark wall of earth shifting towards him" (11.43). Does she kill Leo's mother herself, or does she scare Leo into using his flame, so that it's he who burns down the building? People die all the time in Greek myths, but in The Lost Hero, Leo's mom, Esperanza, is really the only person who is killed violently and permanently. In a book that often feels like a videogame (see the "In a Nutshell" section for more on this), Leo's childhood is the one passage that functions more like Greek tragedy.
At the same time, Leo is in many ways the character who is least myth-y (which totally isn't a word, but you follow). We're pretty certain there are no pipe cleaner helicopters in Greek myth, and nor are there computer-controlled dragons, construction equipment (which Leo keeps using to bash the bad monsters), magic tool belts, and so on. Leo's various accessories are one of the most obviously videogame-influenced aspects of The Lost Hero, and just like in games, useful items appear from nowhere, as though Leo has magical bottomless pockets.
There's a lot of talk in the book about Jason being the bridge between Greek and Roman camps, but the main split in the book isn't really Greek/Roman—it's ancient/modern. In this regard, Leo seems much more pivotal than Jason. Leo's dragon made out of metal is emblematic both of his place in the book and of how the novel as a whole works, with myths retooled and revamped so they are shiny and cool and cute, while maybe being a little dangerous still. Leo lives in a world where you see the face of a nightmare in porta potty sludge—and then get to bash that nightmare with a toilet seat.