The choice of language in this game makes me wonder if English is your native language. I mean no offense nor disrespect, but there's a couple of things that I've noticed so far. I'm only on Chapter 2.
First off, the word 'vassal' refers to someone who has sworn fealty to a liege lord. Such as a landed knight being sworn to his King or Lord. I think the word you meant to refer to Fa was Vessel, which is something that is used to hold something else. Like how a bowl is a vessel for soup, or a boat is a vessel for people or cargo.
Second off, military terminology. The rank of corporal is a fairly low rank, in many most armies. A corporal is the lowest level of enlisted leadership, usually directly overseeing newly enlisted soldiers. They're not even part of the officer corps. I think that a Captain would be more appropriate a title for someone leading the kind and numbers of troops in these chapters. An officer with leadership training and experience.
I realize that this is a game, and it's meant to be enjoyable, but seeing these errors is picking at me, and breaking my sense of immersion... and I can't be the only one.