The Horn of Huitzilopochtli was a triceratops born on Aztlan 50 years before Book 1. His parents were killed by bandits when he was only one month old. Almost as soon as he was old enough to talk, he noticed all of the statues of the God Huitzilopochtli in the secluded mountaintop temple he lived alone in and dedicated his life to serving Huitzilopochtli. Unknown to him, however, he was the last surviving descendant of the Lords of Xibalba, meaning he could use Astral Magic to open a portal to Xibalba is he so desired. Foreseeing this being's importance in the fate of the universe, The Norns cryptically wrote him into the Prophecy of Two, using the phrase "The Horn Will Call" as a reference to his species since he did not have a name due to his parents' death. He was referred to by those on Aztlan as the "Horn of Huitzilopochtli" and the name stuck. Once Tate and his forces arrived in the mountains of Aztlan, they used tainted agave to brainwash the Horn of Huitzilopochtli to join them. He then used Astral Magic to open a portal to Xibalba, which he, Tate, and all of Tate's warlords promptly walked through. It closed before Weasel or any of his friends could enter. The Horn of Huitzilopochtli was killed when Xibalba struck Aztlan.