This is a term which refers to ancient weapons and tools with hidden supernatural powers that appear in myths and folklore from all around the world. Relics are impossible to create without the use of heretical technology, which is lost in the current era, but they have been successfully excavated throughout various ruins in the world.
Due to the passing of time these artifacts have suffered much deterioration and damage. Even in large-scale excavation projects, finding pieces that are completely intact is incredibly rare. Therefore, in most cases, only "relic fragments" have been recovered. Relics that are in a grounded state can shift into an active state through the power of song, thereby releasing their inner power.