So, Ghetsis is sitting there right, and decides he wants to adopt a kid to become that "King of Team Plasma" thing he wants. Finds a little autistic thing with the same hair color as him, figures he'll do, and starts raising him alongside Pokémon in order to set the stage.
Right, that's pretty much confirmed. Here's where it gets weird though. Ghetsis learns the kid has a fatal heart condition. Well fuck, he says, I need this kid. Human heart donors are hard to come by, though, so instead of waiting and hoping for one, he decides to give N the heart of his friend Darmanitan. As a result of having a literal Pokémon heart, N finds himself able to speak and connect with Pokémon better than anyone else in the world.
>So you came. The freak without a human heart.