William the conquerer was half dragon half human and because of his dragon health he lived for longer so took over more of Europe and started the Wyvern Empire. He had a treaty signed between humans and dragons. Dragons couldn't eat humans and keep them as slaves and humans could no longer hunt dragons and all dragon hunters had to stop hunting dragons or they could be eaten.
The dragons are advanced technology wise but mostly it is about physics but they shared some of their knowledge with the human. Humans either didn't take it all in or took the knowledge in another direction and that is where the steam-powered technology comes from. There is also a lot of clockwork but in contrast, there are computers and AI created with crystals.
Gideon- Mathematician, dragon. He was the one that found earth and encouraged people to travel from their home planet. He traveled before the others so was able to hide amongst the humans and learn human mannerisms. He spends his time bouncing from University to University working on different projects. Brother to the Dragon Emperor.
Hara- An ex-con artist who turned straight when her father abandoned her to the authorities. She is descended from two of the most brilliant engineers and is probably the next genius but because of her history, no one is willing to trust her inventions. She has a complicated history with her father. This mix of fear and brilliance is what draws Gideon to her.
Murphy- Weapons specialist. He likes his weapons which isn't a cheap hobby so he finds jobs where the person is willing to subsidize his hobby. When he stumbles across Hara he realises that he can get the weapons as they are being invented so is super loyal to her. He matches her well as he has no ambition to be more.
Alice- A scholar from a small town she is accused of being promiscuous by her beau and has to flee due to the scandal. she appreciates having a place where she can be use her mind and yet still be feminine. She is the only one on the ship who still wears skirts all the time.