I consider my char Alfons to be a pretty successful spy at a time. He joined Neo Grehk and became judge fairly quickly in the tiny realm, using the position of power and influence to convince the general to attack Vore (which was a city of the warring also tiny Fronen at the time). The attack was successful but at the moment of battle, my char turned around with his sizable unit and lots of siege engines and publicly invited the Old Grehkian army into the city, claiming some crap about disorder amongst the peasants due to starvation. He also joined Old Grehk and took part in the assault, all while the Neo Grehkians were fighting a casualty-heavy battle in a walled city. A long and messy TO followed and after Vozzessdor had 25k less peasants, he became Duke of it.
Then he did some stuff with that Duchy and started working against the government of OG but that wasn't very successful, except for the hurting OG part.
P.S.: Probably should've mentioned all the info-sharing he did whilst bringing these plans to fruition with any realm that he could benefit from. That's after all pretty much the thing that made him a spy...
