Queen Isabelle is the queen of the Kingdom of Fonseine.
Isabelle is an elegant woman with light-colored hair tied back into a bun.
Isabelle seems to be a gracious, polite woman.
Queen Isabelle, along with her son Claude, visit Weisburg Palace, with the entire court present. She mentions how it has been a long time since she had visited and introduces her son. Leonhard graciously greets her, and she remarks on how he had grown into a fine young man. Heine, noticing that Leonhard is repeating the same words when greeting everyone from Fonseine, asks him about it, prompting Isabelle to ask who he is. Heine introduces himself as the royal tutor, which Isabelle finds impressive as she assumes that he is a genius little boy. Viktor asks Heine, Leonhard, and Adele to take Claude on a tour of the palace while he and Isabelle discuss about things.
Later, after the delegation from Fonseine leaves, Viktor mentions that he was discussing Eins' marriage with Isabelle, and they had planned on introducing Adele and Claude on this trip.