Resilience is a defensive stat that is generated when you are targeted by Black Ops during a war.
Spy resilience increases the recovery of wizard strength and is gained when targeted by spy ops.
Wizard resilience increases peasant growth and is gained when targeted by hostile spells.
Generating Resilience and Formulas
Resilience is generated when you are successfully targeted by a Black Op. There are two kinds of Resilience: Spy and Wizard, each corresponding to the type of op that you took damage from. The amount of resilience gained depends on what you are targeted by. Spy resilience is generated at 10 resilience per successful op. Wizard resilience is generated at 10 resilience per successful op. These numbers are not modified by anything in the game, and always decay at the same rate: 8 resilience per tick elapsed. Additionally, if the op failed, i.e. the spies were caught or the spell was repelled, then no resilience is gained, nor do you gain any when you use Energy Mirror to reflect a spell back to sender. You also need to receive actual damage in order to gain resilience. Having your non-existent boats sabotaged gains no Spy resilience.
Spy resilience increases the recovery of wizard strength by
SpyResilience / 250
Wizard resilience increases the maximum peasant growth percentage to
(WizardResilience / 250)%