Nouveau is a messenger from the star Flowern, sent to Earth alongside the cat Cateau to locate the flower child destined to find the Seven Color Flower. On Earth, Nouveau takes the form of a large talking dog, though his original appearance is that of a middle‑aged man. He is characterized as reliable and relaxed, often providing steady support to his companions during their journey.

His primary motivation is to fulfill the mission given by Flowern’s ruling family: to ensure the Seven Color Flower is found so a new ruler can ascend the throne. This duty is what drives him to seek out the flower child, who turns out to be the orphaned girl Lunlun. Nouveau plays a central role as a guide and companion, traveling with Lunlun and Cateau across Europe and assisting in various encounters along the way.

Key relationships include his partnership with Cateau, with whom he shares the responsibility of completing the quest, and his friendship with Lunlun, whom he respects and aids without hesitation. Throughout the story, Nouveau remains a calm and dependable presence, offering advice and encouragement without seeking personal glory. His development focuses on his steadfast loyalty to the mission and to his friends, rather than dramatic personal change.

Notable abilities include his capability to speak and reason like a human, as well as his ability to shift between a canine form on Earth and his original humanlike form. He does not possess overt magical powers, but his wisdom and relaxed demeanor often help the group navigate challenges.