Heroes of Land, Air & Sea

During battle in the C.C., how are the serfs on the Action bar, in Buildings, and in the Courtyard affected by removal spells (e.g. Fireball), removal abilities (e.g. Dragon), and other spells?

Serfs on the Action Bar and in Buildings cannot be removed with removal abilities/spells or sacrifice. Other than that, they count towards every other ability/spell, weakening or boosting.