I wonder if they(dev) will do something with the kid & 'real' world. It's one thing with other NPC accepting players/immortal just disappearing once in a while, since it just how things are, but as someone who was born from one, have not been taught conventionally, and have multiple talents in regard to high curiosity & talents, it would be weird if Lord isn't a tad curious.
Air & space exploration used to seem like crazy ideas until there are break through, then the question went from "is it possible" to "how can we improve". As Greed & the other regularly disappeared, Lord getting the idea that that is a skill he will learn in the future is not a far-fetched idea.