Damemon is a Mutant Digimon. It is a Digimon that was accidentally born when the waste data drifting through the Digital World randomly combined. Since "No good, no good!" (ダメダメ！ Damedame!?) is its favorite phrase, it has a bad habit of criticizing people without reading the atmosphere, regardless of the person or situation. Although it is the sort of person that is definitely the #1 "No good, no good!", somehow it has gotten by with the help of its partner, Tyutyumon. Together with Tyutyumon, Damemon can finally be said to be a full Digimon. Tyutyumon stays on the "Tyutyu Tray" on the back of Damemon's head, and takes it along to various places to go play. When the two of them are together, every day is Priceless.