Lunamon originally lives in the Disc Zone. She is horrified when Kiriha kills the Zone's elder, Mercurymon, and she remains on the sidelines during the fight between Blue Flare and Blastmon, while also being scared of the Disc Zone falling apart. Despite Xros Heart's efforts to keep Kiriha and Blastmon's forces from damaging the Zone, it breaks apart and is lost in the Digital Space. In a last ditch effort, Mikey puts the Zone's inhabitants, including Lunamon, inside his X Loader and Zone Transfers back to the Shinobi Zone.
There the Monitamon generously offer DigiNoir and their home to the Disc Zone refugees. During the party, Shoutmon gives his DigiNoir to Lunamon as a gift, and after she eats it, she decides to keep the container as a reminder of Shoutmon's kindness. However, during his attack on the Shinobi Zone, Blastmon knocks Shoutmon X4B into Lunamon's hut. Even though Zenjirou saves her from harm, the DigiNoir container is crushed as well, which causes Lunamon to cry. Enraged by this, Shoutmon X4B vows to become a true king, and never let anyone cry when his reign begins. With the help of Nene Amano, Shoutmon X4B digixroses with Sparrowmon to form Shoutmon X5B, and destroys Blastmon's body, leaving only his still-living head behind. Shoutmon and Lunamon have one more moment together, before Mikey hears the melody of a dying Spadamon and goes to investigate.
She later appears along with Coronamon and Spadamon as brainwashed crew members of Olegmon.