The Caern's wards were originally constructed by Warstripe to keep spirits sent by a Mage, Kashiwagi, away from the Caern. Stormcrow, Thorn, Crisium, and others improved upon them. They were built in three layers: the 'outer' wards, the 'inner' wards, and the 'ring'. After the Wheel's destruction, the wards were gone. With the restoration of the caern, the wards needed to be replaced, and the task fell to the Warder, Gatekeeper, Groundskeeper, and other spiritually minded Garou for the most part. They began gathering spirits allied with the Wyld, and the new Caern's totem, Fog.
Lunes, wyldlings, fog jagglings and gafflings, as well as water, air, and earth spirits can all be found within the confines of the caern, lending their energy and ability to its protection. These are the fruits of labor sown by the Garou of the Walk themselves--those that have spent time to encourage these spirits to make the caern their home.
But the caern has a more self-maintaining defense system that comes directly from the power within it, fueled by Gaia Herself. As long as the Garou keep the Caern healthy, (with song, gnosis, ritual, etc.), these 'inner' and 'outer' wards will be continually at work. They, along with the spirits, make up the Caern's defensive wards. See also: CAERN WARDS OUTER , CAERN WARDS INNER , CAERN WARDS RING