The Kinder might or might not be vassals. Anyone sworn to Flint would also now owe allegiance to Ricther by their oaths. All the unsworn people of the Kinder settlement would be denizens. Even if they swore oaths they would still only become vassals. Many of us don’t realize that citizenship isn’t always granted because today most people are born citizens in the country which they live. In the Roman Empire people born in Italy were not necessarily citizens either. Many people had to earn their citizenship by serving for a term of military service. I know the US, France, and I believe Britain still allow for this type of citizenship. I’m not familiar with Denmark or other countries.