Fyri
Inkling
Hmm! Yeah! In that case, I guess you'll really just want interesting characters, not necessarily fighter types.
Anyone can become a martial artist if they have a good enough reason. It might be better to start with the type of person you want these later dragons to be. Who would be more interesting for your existing characters to interact with? After figuring that out, then you can fill in their backstory and what kind of martial artist they are.
You might even (if you are brave enough) go around and ask people in real life dojos why they study their chosen art. (You might even study them as a person a little. Writers are detectives~ Just don't look too suspicious. )
Anyone can become a martial artist if they have a good enough reason. It might be better to start with the type of person you want these later dragons to be. Who would be more interesting for your existing characters to interact with? After figuring that out, then you can fill in their backstory and what kind of martial artist they are.
You might even (if you are brave enough) go around and ask people in real life dojos why they study their chosen art. (You might even study them as a person a little. Writers are detectives~ Just don't look too suspicious. )