Not that I haven't played Suikoden II two dozen times, but I've never gone back to Rockaxe castle to get the recipe and thunder rune from there after you overthrow Knightdom. Guess I've never thought about it. Soldier outside Gorudo's office gives you a thunder rune and the bookcase has a nice steak recipe (cause you can't figure out how to grill a steak without a recipe)
But jeez, no wonder Gorudo is such a jerk. Can you imagine how annoying it would be having to follow that path every day on your way to your office? That can't be easy for a hefty older gentleman such as himself.
Think about it. He's taking the 20 minutes to walk to his office, and there are these brats loitering in the halls when he's so close to making it. I'd probably order my crew to pelt them with arrows too. The man just wants to drink his coffee and check his stocks in peace.
Get that man a Viki and a blinking mirror for crying out loud.
"Black Rune, pink balloon! This guy killed Gremio!!!"