The Song of Shadow is a Shadow Artifact created when the Celestial Raptor sung his powers of Shadow Magic into a song before he died. Since he thought that having the lyrics buried with himself when he died was too obvious of a choice, he entrusted it with the Lords of Xibalba, priests who were in charge of keeping the asteroid Xibalba from crashing into Aztlan. Once the Lords of Xibalba died, it would be impossible for anyone to learn the Song of Shadow, or so the Celestial Raptor thought. However, 35,000 years later, when Tate came to Aztlan, he used a soul-stealing box to go through the step pyramids of Aztlan where the Lords of Xibalba were buried and retrieve their souls. After destroying Aztlan, Tate took the souls to Ryu 108, where he forced them to teach him the song, allowing him to use Shadow Magic. Now that their souls have been set free after the incident, one must go to Heaven to learn the song from them.