I am currently writing a short story, for a text prompt demanding I set my plot among medieval Japan's nobility, but I am unfamiliar with older honorifics.
The main dialogue takes place between a military commander of high nobility and his first lieutenant and bodyguard. The point is that although they have no hierarchical intermediates, the commander's blood is much more aristocratic than the other's, which demands immense levels of respect from him.
If the lord is a samurai, what would be the title of his first lieutenant? How would they address one another, both in terms of particle ( -kimi? -sama? "O-"prefix?... ) and of designation (a title, a last name)? Could there be several possibilities?
Is there a more fitting title than samurai for this type of subordination relationship (for example, is it unrealistic that a samurai would have a first lieutenant serving as body guard)? In which case, does the lieutenant also have a title I should be aware of?
What could be address variations (for different tones), such as between the English "my lord"/"lord X"/"master"? And, the other way, "lieutenant"/"lieutenant X"/"X" or even a (slightly condescending) "my friend"?
Bonus question, like this wasn't enough yet: raking through even my most guilty references, I looked up the term taicho for captain and only ever found pages about the anime Bleach. Does this rank even exist in real life (along with fuku-taicho)? That's just me being curious however, I believe I can absolutely not use them.