Oops. I forgot to mention that! The sun will go supernova if @Flipped99 adds water and increase the solar mass beyond the Chandrasekhar limit. Thanks for pointing it out.
Not only Edgar but Grey was a train baby too. They both are teens. As they grew up at the back with cars full of people and noises they might not have developed the hearing ability. But Yona, being the engineer’s daughter might have had the right environment to have developed some echolocation ability along with her addiction to Kronole.