In the anime Hana no Ko Lunlun, the character known as Celi is also referred to by the name Serge Flora in some versions and is a central figure in the story. He is a mysterious and kind-hearted young man who travels across Europe, often appearing in the same locations as the protagonist, Lunlun. By profession, he is a skilled photographer and an avid traveler, using his camera to document the beautiful landscapes and places he visits on his journey.

Celi's personality is defined by his gentle, supportive, and patient nature. He is consistently portrayed as a sweet and understanding individual who acts as a guardian figure to Lunlun, offering her help and encouragement whenever their paths cross. Unlike the more impulsive Lunlun, Celi is calm and composed, carrying an air of mystery about him that hints at his true origins. His primary motivation is to support Lunlun in her quest without directly interfering, guiding her progress in a subtle and indirect manner.

Within the story, Celi fulfills the crucial role of a silent benefactor. He is often seen at the end of an episode giving packets of flower seeds to the new friends Lunlun has helped. These seeds are not merely gifts but serve a greater purpose, as the flowers grown from them eventually contribute to the creation of the legendary Flower of Seven Colors that Lunlun seeks. His relationship with Lunlun is the emotional core of his character arc. While she develops a strong admiration and crush on him, he reciprocates her feelings more subtly, ultimately revealing his deep affection for her. He shares a supportive bond with Lunlun's animal companions, but his most significant relationship is with her, evolving from a mysterious stranger to her destined partner.

Celi undergoes a significant development over the course of the series. While he initially appears as a traveling photographer, it is eventually revealed that he is, in fact, the Crown Prince of the Flower Star. This revelation explains his profound connection to flowers and his mission to find the heir to the Flower Planet's throne. At the story's conclusion, he makes the ultimate choice to renounce his celestial heritage and remain on Earth to live a simple life with Lunlun, becoming her official romantic partner. Regarding notable abilities, Celi possesses an inexhaustible supply of magical flower seeds, which he gives to people as symbols of their personal growth and lessons learned. His most significant ability, however, is not magical but his unwavering support and wisdom, guiding Lunlun toward fulfilling her destiny without ever taking center stage.