I know a lot of the plot of this series, but have no clue on author/titles. Bought the books in Germany at the PX. But they were selling in the USA when I got back. American author I think. Late 1980s or early 1990s.
Spaceship Captain, kind of down on luck loser. His old war/military buddy runs a starbase and is kind of at the end of being able to help him. Captain owes money, lots of money. The starbase captain says he can 'fudge the spillage reports and give him some fuel'. At this time, a young man is desperate to get off of the planet, and a forced marriage. This young man mentions something about a farmer and his daughters and a 'three ring ceremony'. He talks himself up and the captain accepts him.
The Captain and Y.Man are in the spaceport, and when the young man (Y.M. from now on) touches this giant window, the captain warns him to be careful or it might shatter and kill them all. The Y.M. is scared - the captain wonders in his mind how much the YM knows, but jokes 'hell, one of those cruisers would just bounce off of this window'
The Y.M. learns of the captains debts when they leave, and suggests they start going after spaceships that they can grab on repossession and get a lot of quick steady easy money. The captain can't believe him, or the fact it was so simple an idea and he never thought of it, but they start, and it's a great success. They are rolling in money, improving lifestyle and the ship. The Y.M. strongly suggests the Captain pay off his debts - the Captain kind of backlslides into his old habits and does not pay the debts.
This has consequences. I think a repo ship or cargo / debt then involves the Space Yakuza. Gangsters in space - great stuff! They are now on the run. The Y.M. then remembers some ancient tradition where if you walk in boldly and without fear into the Yakuza leaders place, and give them the money, they have a tradition of respecting that. They do that, but it gets more complicated with that group.
Now, down the line, this goes way crazy great. The Young Man, through alien technology I think, accidentally inherits the spirit/intelligence of a legendary General (maybe admiral or just hero) who saved humanity from alien attack, but when total xenophobe. I think he drinks a vial of something, or it's forced on him.
This leads to more encounters where this legendary warrior will 'possess' him a bit, or at least strongly make him a bit of a xenophobe towards aliens and the captain at some point does not know how the Young Man will react in any situation.
I thank you for reading this. Great books, good action, good writing, again the normal thin size science fiction novels.