Elisabeth "Sissi" Delmas is a mean, conceited, spoiled and "popular" student at Kadic. She often pesters Team Lyoko, most of the time to win Ulrich or Odd's affections. However, it seems that her actions toward Team Lyoko is an attempt to gain attention and respect from them, as she admits in Holiday in the Fog, much to her tearfulness. She is also the daughter of Jean-Pierre Delmas, the principal of Kadic, the boarding school she attends and lives in. She even has her own room there.