The Rites of Protection and Passage are a varied set of enchantments and wards utilising different types of magic to repel and contain intrusion. The culmination of the Rites resulted in the construction of defensive structures known as kaers and citadels.
The Rites were designed by the Theran Empire to provide Name-givers with a means to escape the worst ravages of the Scourge. The methods often required large quantities of the True elements (earth, fire, wind, water and hear- ah… wood), and orichalcum. As the time of the Scourge approached, skirmishes broke out contesting these precious substances. The greatest of these conflicts became know as the Orichalcum Wars.
The theory surrounding the Rites at their inception suggested that the strongest element of protection would be that of earth. Aside from the fact it makes an effective physical barrier, earth's pattern prevents passage through astral space as it is "living". Therefore it was believed that sheltering in underground structures, dubbed kaers, would offer the most assured means of defence. Another aspect of the Rites was subterfuge - those kaers that remained hidden would never have the need for their defences to be tested. This was more easily achieved by building upon existing cave systems, or disguising the entrance of kaers as natural rock formations.
Defensive structures above ground, especially cities that weren't abandoned, became known as citadels. Methods devised for protecting these settlements included surrounding the locality in domes of True air and True fire. Very few citadels survived the Scourge however, as they were quite conspicuous and Horrors seemed to make a point of breaching their defences.
As any opening to a fortification is a weak point, entrances were often heavily warded with magic. Such wards were designed to ensnare or entrap Horrors and often used orichalcum to enhance their power. More mundane devices were also used, such as mechanical traps. These wards and traps were usually designed to renew or reset themselves, and adventurers that discover empty kaers may still need to contend with them.
The Rites are an artifact of the setting so are never described in detail, and due to their varied nature are not provided with mechanics.