Potential Solution

Once their negotiations ended, Rui retired to the provided luxury quarters in the imperial palace of the Britannian Empire, getting some rest to recuperate from the several times he had ended up using his Martial Mind briefly to dispatch some beasts and monsters.

He reflected back on his talks with the Prime Minister. 

Much of the initial parts of their conversations had been about hashing out their most intense disagreements. 

Prime Minister Edward hadn't seemed to care about treating Rui with stuffy formality as he would any other ambassador as important and powerful.

Perhaps he had known that Rui would not be comfortable with it and would rather avoid having to do things that way.

Perhaps he would rather address Rui with a hint of familiarity since they had already contended once in a now irrelevant war when they both fought for the loyalty of the Shionel Confederation.