In order to use spies on someone (wether it is for spying on them or perform an espionage),you have to have a spy first.Spies can bought from marketplace (if the city sells them) and doing so requires one mp in addition to some gold.You can only have one spy per continent.
Spying[]
Spying is the act of gaining intelligence about the target's kingdom which can be seen later in the report section of the guild tab.It is Always recommended to spy before attacking anyone and against experienced players and inactive NPCs who regenerate troops after each attack it's also recommended to spy them before each attack and not just the first time.There are multiple ways to spy on someone,you can use your spy,use skills wether from your class or your hero and also use Eye of Oracle .
All of the options mentioned above have 100% chance of success except when using spies,in that case the base chance of success is 80%(affected by Age Modes ,Classes,Artifacts and heroes).If a spy attempt is failed the target will get notified of your attempt and your name,and either the spy escapes,dies or reveal your own information to the target.Spying by using spies requires 2 mp.
Most of the spy options are continent specific the exceptions are the True Sight spell and Eye of Oracle .
Espionage[]
Performing espionage on someone always costs an attack but it is not a physical attack meaning it can pass protection.
Arson[]
If successful it destroyed between 1-5 structures.
The base chance of success is 80%.
It costs 3 mp and 10k gold.
Poison[]
It can kill between 10-20% of peasants.
The base chance of success is 80%.
It costs 3 mp and 10k gold.
Steal[]
It can still between 10-20% of the target's gold.
The base chance of success is 80%.
It costs 3 mp and 10k gold.
Burn[]
It can destroy between 10-20% of food.
The base chance of success is 60%.
It costs 4 mp and 20k gold.
Forgery[]
It steals a structure's worth of land (900 or 1000) at max.
The base chance of success is 60%.
It costs 4 mp and 20k gold.
Raid[]
It steals between 5-10 magic items,depending on which items you have this number could decrease.
The base chance of success is 60%.
It costs 4 mp and 20k gold.
Dismiss[]
It can dismiss the target's hero.
The base chance of success is 40%.
It costs 20 mp and 100k gold.
Remove[]
It can remove the target's artifact.
The base chance of success is 40%.
It costs 20 mp and 100k gold.