Counter Guardian (カウンターガーディアン, Kauntā Gādian?), also called the 'Protectors of Balance' (抑止の守護者, Yokushi no Shugosha?) or the Beast of Alaya, is a broad classification of Heroic Spirits made up of heroes who are not worshipped, utilized as a mindless Counter Force. Other Heroic Spirits have a high Divinity and act as existences closer to the planet than humanity, so they are able to avoid being drafted by the Counter Force. Normal circumstances are those where the Counter Force empowers a "normal person" in life to remove the factor that can trigger destruction, eventually causing them to be worshipped as heroes. Those who become heroes in such a manner are then used as Counter Guardians, the "Counter" emphasized because they act with no autonomy of their own and only appear in response to an event.
Usually Counter Guardians vastly more powerful than Servents