| Sgt. Lilly Madison Mueller|
|Family||Lt. Mueller- Father (Deceased)|
|First Appearance||"Warren's Dream"|
|Last Appearance||"Escape from Altura"|
|Death Episode||"Escape from Altura"|
|Cause of Death||Devoured by Zombies. Blew herself up with a grenade.|
|Series lifespan||"Warren's Dream" to "Escape from Altura"|
Nothing is known about Sarge prior to the apocalypse other than that she was part of US military.
Sgt. Lilley is mildly seen in the background of this episode.
Sgt. Lilley is part of the team looking for the missing convoy. During the search, Sgt. Czarnecki is shot by a soldier from Zona. Sgt. Lilley is forced to give him mercy, but even though he is given mercy he comes back as a zombie.
Sgt. Lilley, along with Lt. Mueller goes looking for 10K . When they get separated Lt. Mueller is killed by Sgt. Czarnecki, after returning to the camp as a zombie, Sgt. Lilley is forced to empty her gun into him in order to kill him. Lt.Mueller is buried at the campsite. Sgt. Lilly takes out half a photograph depicting Lt. Mueller and leave it as his grave, along with the other half that Lt. Mueller carried with him. She then joins the group heading east following Roberta Warren.
Following Warren's dream, the team doesn't stop while crossing The Great Pile, a seemingly endless landscape of rubble and destruction. while trying to evade soldiers from Zona they encounter the Enders living among the cars. They are robbed of weapons and food.
Sgt. Lilley, along with the group, investigate an abandoned truck. A high sound is heard and the group members pass out. They awaken locked in wooden crates. As Roberta is starting to lose grip Sarge tries to calm her. She tells the story of how she was once trapped in the trunk of a car for 9 days after her family turned zombies. At one point; she is dragged out of the crate she was supposed to wake up in while still unconscious and is nearly sexually assaulted after she wakes up. Instead, she pushes the man into a zombie that was behind him and escapes. She finds a bird in a staircase she escapes to which helps aid the rest of the group in their escape of the building they're all trapped inside. With the help of a zombie named Carson, O'Keefe, eventually, the group manages to escape the building complex.
- Her birthday is on 17 November 1992.