Iwabe Yuino is a genin from Konohagakure and a member of Team 5, alongside Metal Lee and Denki Kaminarimon. He is notably older than his classmates, having been held back in the Ninja Academy after failing the graduation examination twice. This experience is the root of his initially abrasive personality.

As a child, Iwabe dreamed of becoming a famous and powerful ninja, and he consistently scored top marks in all practical and physical exercises at the Academy. His struggles were purely academic; his strong aversion to book studies and subjects not directly related to ninjutsu led to poor written test scores, which prevented him from graduating. Frustrated by a shinobi era that demanded both physical prowess and academic knowledge, he became rebellious, often skipping classes and bullying younger students. He valued strength above all else, believing that the constant struggles of past warring eras were what truly forged powerful ninja, and he looked down on his peers for taking the peaceful times for granted.

Despite his contempt for the modern system, Iwabe holds a deep admiration for Naruto Uzumaki, the Seventh Hokage, seeing him as someone who became the strongest ninja despite facing immense adversity. This admiration is shown through small details, such as his great joy in acquiring a rare Naruto trading card. His attitude began to change significantly after meeting Boruto Uzumaki. Initially resentful of Boruto, viewing him as a privileged son of the Hokage who received special treatment, Iwabe was surprised by Boruto's determination and refusal to give up. A fight between them helped Iwabe realize that he was being a hypocrite, blaming others and the era for problems he was not honestly trying to solve. Following this revelation, Iwabe became much more civil, attending classes regularly and forming genuine friendships.

He develops a particularly strong bond with his teammate Denki Kaminarimon. Their relationship is mutually supportive, as Iwabe helps Denki improve his physical and ninjutsu skills, while Denki tutors Iwabe in academics, helping him find creative ways to concentrate on his studies, such as using chakra to walk on walls while reading. His friendship with Metal Lee is built on a mutual respect for physical prowess and hard work. While he has a high opinion of his own abilities and can be short-tempered, he matures into a more reliable and loyal friend. His role in the story is that of a supporting character whose journey emphasizes the themes of growth, perseverance, and overcoming personal shortcomings. He participates in many key arcs, including the Academy entrance arc, the school trip to Kirigakure, the graduation exams, and the Chunin Exams.

Iwabe Yuino possesses remarkable combat aptitude, excelling in taijutsu and ninjutsu, which is why his failure to graduate due to written exams was such a point of frustration for him. His primary specialty is Earth Release, which he uses with great creativity and control. He can form defensive walls, create projectiles, and shape the earth around his opponents to trap them. His signature weapon is a bo staff, which he can infuse with his earth-based chakra to transform into a large mallet or other weapons to deliver devastating blows. The staff also conceals a sword, demonstrating his versatility in close-quarters combat. Later in his development as a genin, he begins training in medical ninjutsu, showcasing his desire to expand his skill set beyond purely offensive capabilities.