Ai Hibiki is a central character known for her energetic and free-spirited nature. She is a lively girl with a straightforward and warm-hearted personality, though she can be impulsive and sometimes unaware of her surroundings. Her primary dream is to become a Traveling Mosa, a legendary and strong wanderer, a goal that drives many of her actions throughout her journey.

Before becoming a traveler, Ai was a member of the North Tama Dangers, a local clan or group. During a conflict at an amusement park, a runaway roller coaster posed a danger. Unlike her fellow members who held strong hostility toward the rival Tokorozawa clan, Ai did not share that animosity and was the only one who attempted to stop the roller coaster. This incident led to her being expelled from the group.

Following her expulsion, Ai quickly joined Nozomi Moritomo and her friends on their travels, asking for a ride from Nozomi despite her former group being rivals. Since Ai does not have a driver's license, she always rides in the sidecar of Nozomi's motorcycle. Her main motivation for joining the journey is to obtain the Stones that are part of their quest, as she believes they will help her achieve her goal of becoming a Traveling Mosa. During the group's adventures, she is often the one advocating for collecting the Stones as payment for their services.

Key to her development is an incident where she mediates a dispute between two other characters, Haru Fujiwara and Ura Kukino. This event marks significant personal growth for Ai. It is symbolized physically by the appearance of the number "2" on her back, which later changes to the number "3", representing her progress on her journey. She is known for her unwavering loyalty to her friends, a big heart, and a tendency to become comfortable in new situations very quickly. Ai has a great love for meat dishes, with favorites including hamburg steak, grilled meat, and curry rice. As a child, she was affectionately called by the nickname U-tan. Her birthday is August 18.