Code Lyoko: Waldo "Franz Hopper" Schaeffer

          Waldo "Franz Hopper" Schaeffer (voiced by Paul Bandey in Season 2, and Alan Wenger in seasons 3 and 4) is the creator of the supercomputer, Lyoko, and XANA, as well as Aelita's father and Anthea Hopper's husband. He was once a science teacher at Kadic, having been replaced by Suzanne Hertz after his disappearance 9 years ago. He lived at a house near Kadic called the Hermitage with Aelita, and before that had a home in a mountainous region. Franz Hopper built Lyoko and XANA to destroy a military project called Project Carthage, which was designed to disrupt enemy communications. Lyoko was later adapted to serve as a sanctuary for him and Aelita, an apparent result of his suspicions that someone was watching him. Upon fleeing to Lyoko, however, Aelita and Franz were attacked by XANA. Franz unsuccessfully tried to reason with XANA, and when that failed he shut down the supercomputer, leaving it inactive until it was found nearly a decade later by Jeremy. He is a minor character.

Franz has gray hair, beard and moustache. He wears glasses and a white lab coat over a long-sleeved sweater in all seasons.

In "Contact", Franz possesses Sissi to try to contact Jeremy. When she is possessed, at first, she seems to be speaking gibberish, but upon further investigation, it is revealed that she is saying backwards, "I can help you. I want to enter into contact with you now, I'm Franz Hopper. I can help you."

Franz is variously depicted in Lyoko with sphere-shaped constructs. In "Aelita", he is depicted as numerous white spheres, while his appearance in "Distant Memory" is that of a larger purple sphere. Franz Hopper, like XANA, can reach out to the real world through the use of the towers, but not nearly as effectively as XANA can. He helps the warriors at various points in the series, even helping them to recreate Lyoko after its destruction in "Final Round". In "Wrong Exposure", his true name is revealed to be Waldo Schaeffer (the name printed on the folder in the closing credits), while "Franz" is actually his middle name and "Hopper" is his wife Anthea's maiden name. In "Fight to the Finish", he sacrifices himself to give Jeremie's multi-agent system enough power to completely wipe out XANA. The act creates a sense ofirony, considering that the majority of the series was spent trying to rematerialize him.