Belle is a playable non-combat protagonist Agent in Zenless Zone Zero, and the co-owner of Random Play together with her older brother, Wise. At the start of the game, the player will choose Belle or Wise as the main controllable character, with the other becoming an assistant.
She and her brother work together as the Proxy known as Phaethon. In Season 2, they both joined Yunkui Summit as part of an investigation, and to unlock their hidden potential.