Pheromone filters (Patreon)

Pheromone filters are a new invention by the hunters that allow them to prevent the sweet scent of the goddesses from reaching them, this is the reason some enemies won't be affected by it. Higher level hunters wear them along with special lenses that  blurry their sight preventing them from being turned on just by looking at women.

However it will be possible for the girls to level up reaching a point where certain filters won't work and this enemies will be vulnerable to the scent. 

Pheromone squirts will have a level of power, and filters a level of resistance, and as you level up your girl more filters will become useless, other mechanics include removing the foe's filter entirely in certain ways, so this opens more variety for boss fights.