Kukulkan was an ancient and long-lived lifeform who was the last of his species and had an impact on various ancient Earth cultures' beliefs and legends. He has also been identified with the lore of Quetzalcoatl, as well as the legend of the Chinese dragon. Kukulkan's visit to Earth is manifested in history by legends of a winged serpent creature that came from the sky bringing knowledge. These records were available in the library computer of the USS Enterprise. Despite his imposing appearance, he was benevolent.
- It was proven in the video game Star Trek: 25th Anniversary that Kukulkan and Quetzalcoatl were two different individuals.
He visited Earth in the distant past, and was instrumental in the technological and architectural advances of the Egyptian, Mayan, and Aztec civilizations. He also taught them new techniques in art and agriculture. He hoped that they would combine this knowledge to complete Kukulkan's city so the civilizations could live in peace and he would return to Earth. However, none of the civilizations built the city exactly as Kukulkan had designed. (TAS episode: "How Sharper Than a Serpent's Tooth")