Citlalin is an educated daughter of Tlazopilli and Yolotli. She falls in love with Pedro de Dávila. Although Citlalin abides by the rules of what is expected of an Aztec girl, she is a rebel and has very strong opinions about what she feels is right and wrong. Because she is very smart, she is a scribe for the Moctezuma.
When Moctezuma learns that Cortés is traveling towards Tenochtitlán, he sends a group of noblemen including Tlazopilli and other emissaries led by Tziuacpopocatzin to meet Cortés at Quauhtechcac between the Popocateptl and the Iztaccihuatl. These emissaries bring golden jewelry as a gift, which greatly pleased the Spaniards. According to the Florentine Codex, Lib. 12, f.6r., Moctezuma also ordered that his messengers carry the highly symbolic penacho (headdress) of Quetzalcoatl de Tula to Cortés and place it on his person.
On this trip, Tlazipilli brings his oldest children Ichtaca and Citlalin with him. It is here where Pedro de Dávila and Citlalin first notice each other. At night, Pedro is watching the smoke coming out of the Popocateptl volcano when Citlalin approaches him and tells the story of Popoca, who after returning from battle found his beloved princess Iztaccíhuatl dead and decided to offer himself in sacrifice; the gods refused but converted them both in volcanoes instead.