Usopp is a central character from the anime One Piece, known for his role as the sniper of the Straw Hat Pirates. He was born in Syrup Village, where his father, Yasopp, left as a pirate for the Red-Haired Pirates when Usopp was very young. Following the death of his mother, Banchina, Usopp developed a habit of crying out that pirates were coming, a lie he first told to give his dying mother hope. He continued this practice as a way to cope with his loneliness, often running through the village and shouting false alarms, which the residents came to use as a daily alarm clock. As a child, he befriended a sickly girl named Kaya, telling her grand, fabricated stories of adventure to cheer her up, and formed a group of local children he called the Usopp Pirates, appointing himself as their captain.

His personality is one of his most defining traits, as he is a notorious coward and a compulsive liar. Usopp is frequently terrified of danger, and his first instinct in perilous situations is to flee or invent a comical, fake illness, such as "can't-get-on-this-island disease," to avoid conflict. This fear stems from his own insecurity and awareness of his physical weakness, especially compared to powerhouses like Luffy and Zoro. However, this cowardice is contrasted by a deep-seated well of bravery that emerges when his friends or their dreams are threatened. He is also incredibly sentimental and emotional, often crying during moments of high stress or when his crewmates succeed. Despite his fears, Usopp serves as an important source of comedy and the crew's mood-maker, often providing over-the-top reactions and imitations. He is also the voice of common sense, reacting with normal human fear and logic to the crew's outrageous adventures, which helps to ground the story from the perspective of an ordinary person.

Usopp's primary motivation is his dream to become a brave warrior of the sea, much like his father. This desire to be a great and courageous pirate is the driving force behind his character growth. Initially, he suffers from delusions of grandeur and refers to himself as "Captain Usopp," but his journey is largely about reconciling his inherent cowardice with his aspiration for heroism. This internal conflict reached a peak during the Water 7 arc when he felt he was a burden to the stronger members of the crew. His deep attachment to the Going Merry, a ship gifted by his friend Kaya, led to a heated argument with Captain Luffy over its replacement, culminating in Usopp challenging Luffy to a duel for the ship's fate. After losing the fight, he left the crew in disgrace. He later returned under the masked alias of Sogeking, the King of Snipers, to help rescue their crewmate Nico Robin, ultimately apologizing sincerely for his actions before rejoining the Straw Hats.

Within the crew, Usopp's primary role is the sniper and gunner. Beyond combat, he is the ship's gifted inventor and artist; he designed the crew's Jolly Roger flag and created Nami's multi-functional weapon, the Clima-Tact. Before the professional shipwright Franky joined, Usopp was responsible for making constant repairs to the Going Merry, which was a key reason for his emotional bond with the vessel. He maintains a close friendship with the young doctor Tony Tony Chopper, often telling him fantastical lies that Chopper naively believes, and serves as a loyal, if reluctant, supporter of Luffy's romantic and adventurous ideals.

Over the course of the story, Usopp has undergone significant development, growing from a weak liar into a more reliable and capable warrior. His character is defined by his ingenuity in battle, relying not on brute force but on what is known as the Usopp Arsenal. This fighting style primarily uses a slingshot, which was upgraded from the "Galaxy Slinger" to the "Kabuto" and later the "Black Kabuto." He fires a variety of specialized projectiles, including explosive stars, smoke balls, and egg bombs. After the crew's two-year separation, he trained on the Boin Archipelago and adopted a new fighting style based on "Pop Greens," powerful plants that grow instantly into dangerous forms like man-eating plants or giant Venus flytraps. During the Dressrosa arc, his development reached a new height when he unlocked Observation Haki, a sixth sense that allowed him to perceive the aura of his targets from an extreme distance. This ability enabled him to make an impossible sniper shot across an entire island, saving Luffy and Law. This act led to the people of Dressrosa dubbing him "God" Usopp, a legendary title that ironically contrasts with his humble, fearful origins.