According to Oda in a discussion with Mayumi Tanaka, Luffy's voice actress, 'no matter who joins, he always wants Usopp to be the weakest'[17] since it would upset the balance of the story. Oda also states that this is because Usopp is the only one in the entire crew who is the closest in strength as compared to a regular human.
Since early in the series, he has struggled to match the physical feats of the stronger characters and needed his weapons or ammunition to take out foes. He used to be a huge coward and often wanted to run away immediately, a trait he still carries to a lesser extent after his two years of training. This, coupled with him getting easily distracted or confused in battle have often made him less effective than his real potential as a sniper. So far, he appears to have moved past this after his training and takes better advantage of his wit and strategy.
Both his physical and mental strength have all increased greatly during the two-year timeskip, as he was able to quickly dispatch all of Caesar's men on his own. While many of his attributes lie mainly in his ability to hit nearly anything he sets his sights on with his slingshot, he is now shown to be strong enough to keep both Robin, Luffy, and himself afloat in freezing water.
Usopp current bounty is 500,000,000, being the sixth highest bounty within the Straw Hat Pirates (after Luffy, Zoro, Jinbe, Sanji and Robin). However, rather than being a reflection of his fighting abilities, Usopp's bounty being higher compared to some his crewmates is largely because he always manages to stand out during the major incidents he's been in. At Enies Lobby, Usopp was the one who burned the World Government flag and prevented Spandam from taking Robin past the Bridge of Hesitation with his sniping, earning him (as Sogeking) a bounty of 30,000,000, even higher than those of Nami and Chopper who defeated CP9 agents. At Dressrosa, Usopp became known as 'God' Usopp after knocking out Sugar and breaking the Hobi Hobi curse, making him the man responsible for exposing Doflamingo true nature to the country, getting him a bounty of 200,000,000, the third highest among the crew at the time.
Marksmanship
“
I'm a sniper, and backup is where I shine!! I shoot down the enemy by surprise to protect my people!!!
”
— Usopp on his role.
Usopp is an extremely skilled sniper. Since early in the series, he was shown to have inherited much of his father Yasopp's exceptional marksman skills. He has exceptional marksmanship[18] and is capable of turning slingshots into formidable and terrifying weapons.[19] With his skills used in conjunction with unique ammunition, such as the Firebird Star, Usopp can deal devastating damage in long-range combat. In addition to his slingshot, he also has great skill with cannons and other forms of Naval Artillery, enough that the crew views him not only as a sniper, but as their gunner, responsible for operating and maintaining their ship's cannons and artillery as well as using them. His skills include using the ship cannons and the Gaon Cannon of the Thousand Sunny.
His marksmanship is nearly unmatched, accurately hitting Spandam and some Marines from a vast distance of over a mile out-distancing even the guns the Marines had with the wind against him. In order to stop Sugar a second time, he demonstrated his ability to calculate and predict trajectory angles, influence of wind and distance, and even incorporating booster shots into his projectile, thereby allowing him to hit his target located indoors, physically located too far away to even be visualized, through a small opening in a window.
Usopp also has extremely sharp eyesight and has on more than one occasion seen or noticed things before his crewmates. Examples of this include being the first one to see Gecko Moria inside the stomach of the gargantuan zombie, Oars, and being the only one able to see the harpy Monet watching them on Punk Hazard. Later at Onigashima, Usopp quickly spotted some lookouts before anyone else and put them to sleep with his Pop Greens.
Engineering Expertise
One of Usopp's prominent abilities is his resourcefulness and understanding towards engineering (such as easily understanding the tunnel networks made by Miss Merry Christmas). Prior to Franky joining the crew, Usopp served as the Straw Hats' sole unofficial gadgets and mechanics specialist. His creative and resourceful engineering has resulted in the creation of both the Clima-Tact and Kabuto which he can further modify with dials and pop greens. He also appears to be highly knowledgeable in chemistry, being solely responsible for manufacturing the highly innovative slingshot pellets, or "stars", that he uses for ammunition. An example of scientific knowledge is in his battle against Caesar Clown. He understood that even though Caesar Clown had the Gasu Gasu no Mi, therefore making him a Logia-type, he would still explode if he was exposed to fire as he was still just gas. He also understood that a plan would not work as Caesar Clown was in control of the gases around him and that if he removed the oxygen from the atmosphere, the flame would no longer burn.
For other more complex activities, such as acting as the shipwright for the Going Merry, he is largely inexperienced, as he was barely able to keep the Going Merry going doing patchwork repairs. As Franky pointed out, his skills are amateur, and he barely knows how to use a hammer correctly for such jobs. After Franky joined the crew, Usopp gladly let him take over maintaining the ship, even agreeing to Franky's request to assist him. In return, Franky provided a workshop for Usopp to work on his gadgets and creations, something he is more at home with. Even Franky admitted that his skills in gadgets are incredible.
Tactical Skills
Usopp is also a highly analytical tactician with quick thinking and incredible ingenuity in battle, able to use deception and cunning strategies to fight and defeat enemies who are physically more powerful than him. In his battle against Chew, a fish-man and an officer of the Arlong Pirates, Usopp threw a bottle of rum at him, catching him off guard before Usopp destroyed the bottle and ignited the alcohol with a Kaen Boshi, setting him aflame before exploiting the chance to hit him hard with his hammer multiple times to defeat him.
While aboard the Puffing Tom, Usopp used a smokescreen to catch the CP9 off guard, allowing him to quickly grab Robin to escape, although the plan ultimately failed due to Blueno's Devil Fruit abilities and Robin's traumatic fear of the Buster Call.
Due to his ingenuity, Usopp can even defeat powerful enemies with Devil Fruit abilities such as Miss Merry Christmas and Perona. In Arabasta, Usopp exploited Mr. 4 and his partner's teamwork against them by imitating Miss Merry Christmas's speech pattern, resulting in Miss Merry Christmas taking the full force of Mr. 4's 4-ton bat head on. When fighting Perona, Usopp accurately deduced the true capabilities of her Horo Horo no Mi and correctly figured out that Perona was actually using Astral Projection, hiding her physical body inside a room instead of seemingly being intangible like a Logia.
After the timeskip, Usopp's tactical prowess significantly improved. On Fish-Man Island, he used different Pop Greens to implant a series of traps to gain an overwhelming advantage against an Energy Steroid enhanced Daruma, an officer of the New Fish-Man Pirates, and ultimately defeated him. He could stop Caesar Clown from escaping by surprising him with a pair of Seastone handcuffs that he fired at him, effectively negating his Logia powers. Usopp also has an uncanny understanding of psychological warfare. When Sugar regained consciousness and attempted to transform Luffy and Law into toys, he chose to exploit Sugar's newfound trauma towards his tatababasco agonized face by having Kanjuro use his Devil Fruit powers to create the Bagworm, a doll-shaped bullet in the visage of his Ganmen Bikkuri Bako, which he fired towards Sugar, effectively stopping her. In One Piece Film: Gold, Usopp quickly thought of a counter measure against Baccarat's immense luck that she stole from her subordinates to gain an invincible advantage for combat. Usopp used a slot machine to fully deplete all the luck Baccarat stole, which allowed him to blast Baccarat with a SkullBomb Grass at point blank range.
Physical Abilities
While not on the same level as the rest of his crew when it comes to pure physical might,[17] Usopp has learned to compensate for his weaknesses by focusing on his own strengths.
Usopp's endurance and willpower is considerably strong. Usopp also has incredible durability; being able take serious damage from amazingly powerful enemy attacks. After a major battle, Usopp tends to have severe injuries often caused by his determination to reach his goal. He will attempt to continue even with his injuries. Prominent examples of his incredible durability can be observed when Usopp was hit in the face by Mr. 4's 4-ton bat and smashed repeatedly through walls by Miss Merry Christmas, and not only survived, but was able to continue fighting. Also, during the Water 7 Arc, he endured physical abuse from the Franky Family twice while trying to retrieve the stolen money. After being beaten up, Usopp managed to focus enough stamina to fight Luffy and later endured attacks from CP9 and the Marines in Enies Lobby. In Thriller Bark, Usopp was tough enough to withstand the detonation of Perona's exploding ghosts multiple times and a ruthless beating from Kumashi, a bear zombie with immense strength, without losing consciousness. While heavily injured, he can withstand using the Impact Dial to blast the Hippo zombie despite the excruciating backlash that nearly broke his arm. At Punk Hazard, when he was attacked by a giant child, Usopp got back up almost immediately and prepared to attack. He was then suffocated by Caesar Clown with his Gasu Gasu no Mi abilities before taking a direct attack from Caesar's "Gastanet" only to come out of the massive gas explosion with a few bruises. He took at least two of Ulti's headbutts while she was in her hybrid form and still maintained consciousness despite having his skull cracked by said individual.
Another key factor that makes him a valuable asset is that Usopp has impressive speed that he uses in very effective hit-and-run tactics. He managed to run away from Chew for several minutes, despite Chew being a superhuman fish-man. In battle, Usopp uses hit-and-run tactics and works best as part of a team where there are more physical fighters to watch his back. This is due to the fact that he is so high-strung and jumpy, and he often gives into his basic survival instincts: fight or flight (usually choosing flight). While this seems to have changed after the timeskip where he is shown to be more confident in his abilities, Usopp still prefers to avoid fighting more powerful opponents if he can help it.
Usopp's close combat abilities are still noticeably limited. Before the timeskip, Usopp admitted that he could only lift 5kg at most and that he and Nami were dangerously underpowered and normal compared to the other Straw Hats. He prefers to use improvised weapons (like his hammers), as he lacked martial art skills. While he has grown noticeably stronger after the timeskip and can handle himself better against multiple opponents at once, Usopp still struggles against physically powerful enemies who can power through his attacks, as while easily defeated by Page One and Ulti, during the tail end of the Raid on Onigashima, he was able to easily carry both Kin'emon and Kikunojo, each about 4 feet taller than Usopp and Kikunojo clad in armor, after the fierce battle and being wash up from Raizo Restoration of Zunesha's bath.[20]
Usopp had awakened his Kenbunshoku Haki during the latter half of the Dressrosa revolt, as he was able to see auras of Luffy, Law, and Sugar, who were in the royal palace, from the old King's Plateau near the Corrida Colosseum. With this, he was able to pinpoint Sugar's location and snipe her down from such a distance.[21]
Non-canonically, in One Piece Film: Red, he also demonstrated exceptional Kenbunshoku Haki, to the point of being able to use to communicate with his father from afar.[22]
Miscellaneous Skills
Artistic Skill
Usopp builds a "Snow Queen".
Usopp is also a great artist, as he proved in the beginning of the series when he designed the Straw Hat's Jolly Roger after seeing Luffy's poor art skills. A running gag involves Luffy and Chopper building simple snowmen or sandcastles only for Usopp to show off his vastly superior skills with a professional work of his own, which ended up being destroyed in a comical way.[23]
Arachnology
Usopp used to make spiders fight when he was younger and knows how to handle them without being bitten by their fangs or being poisoned in the process.[24]
Lying
Usopp is also an adept liar, which can be useful in certain situations. Although many of his lies are outrageous and easily seen through, they've been shown to be a useful distraction at times, especially against gullible opponents. At times, it even succeeds as a deterrence albeit for a short period of time until his enemies figure out his bluff. He often incorporates his bluffs into his arsenal with mixed results. He is also a skilled sham salesman, often selling worthless items to people by lying about what their capable of doing.
Hairdressing
Usopp also has some skill with hair cutting since he and Robin act as the crew's hairdressers.[25]
Gardening
Likely due to Usopp's time with Heracles, he has gardening skills, which he uses to cultivate Pop Greens for his arsenal after the timeskip.
Weapon Crafting
Due to his engineering expertise, Usopp is able to utilize the available technology and tools to construct and upgrade weapons. Unlike Franky, who focuses on heavy arsenals, Usopp focuses on handheld weapons. His known masterpieces include the Kabuto, Kuro Kabuto, and Clima-Tact. When Nami gave him the components needed to upgrade her Sorcery Clima-Tact from Weatheria, Usopp was able to put all of it together to make the Sorcery Clima-Tact stronger and more efficient.
Usopp's weapon of choice is a slingshot which he used in combination with a variety of pellets for long-range combat.
Usopp has developed other attacks unrelated to projectiles, though they are mainly jokes. These include the 5-Ton Hammer and others. After the Skypiea Arc, he has started using Dials for attacks such as using the Breath Dial to house explosive gas, using the Flash Dial to blind his foes, and using the Impact Dial to absorb and return blows.
Usopp improves his sight and/or focus with special goggles. He purchased an upgraded pair in Loguetown, but the actual scene of him purchasing them was cut out in the 4Kids dub. The scene was also absent in the original manga due to a lack of room. Since the timeskip, he has discarded those goggles, and gained a new pair which he typically wears around his neck.
As the sniper of the Straw Hat Pirates, Usopp focuses on long-range weapons like his Pop Greens. As stated by himself on Onigashima, he does not have a lot of close-ranged weapons (mainly his Dials and Hammers), leading him to use some of his long-ranged tools at close-range, posing danger to both him and his allies alike.[26]
Ginga Pachinko
His first slingshot, also known as the "Ginga Pachinko", was his primary weapon for combat, and he had many different types of ammunition which he carried inside a large shoulder bag of his. He also often uses eggs in order to blind his opponents and rocks whenever he runs out of ammunition (before the timeskip).
Kabuto
Usopp (as Sogeking) using his Kabuto.
In the Enies Lobby Arc, Usopp introduced a new weapon, the "Kabuto", his second slingshot with five bands connected to a long staff. It has much greater power than his normal slingshot because it is powered by Skypiean Dials. Its range is enormous, and Usopp can use it to strike individual targets quite accurately from seemingly impossible distances over a mile.
The exact workings of the Kabuto are unknown, except that the five bands increase stability (and thus range), and the Dials in the instrument add spin to the ammunition similar to rifling to increase damage and accuracy, as well as allowing Usopp to choose a variety of different Dial effects to add to each shot. Usopp explained some of the workings of Kabuto to Perona during their fight but was interrupted before he could finish.
Kuro Kabuto
After the timeskip, he uses a new slingshot called "Kuro Kabuto", which retains the five-band design of the original Kabuto. The only immediately clear difference is that it is colored black and is smaller in size (whereas the first Kabuto was a staff, the new one is nearly the same size as his original slingshot).
Grow Up Kuro Kabuto
His new Kabuto also has the ability to take on a more powerful and larger form that he calls "Kuro Kabuto Chomping Grass". After being given water, it eats up anything in the immediate area, such as rocks and boulders, to use as ammunition. This technique allowed Usopp to capture Caesar, along with Buffalo and Baby 5. He can expand it to an even larger size, which he dubs "Super Grow Up Kuro Kabuto", that is useful for particularly long-range attacks.[21]
After two years of training, Usopp added special seeds called Pop Greens to his arsenal that instantly grow into super plants upon impact; the various types of plants have unique properties and unusual abilities, giving the plants multiple combat applications.[27] This was first shown shown when he defeated some of the Fake Straw Hat Crew by creating a carnivorous plant that resembled a monstrous Venus flytrap with tendrils. During the Fish-Man Island Arc, he also manages to save the crew and the Thousand Sunny from being crushed by boulders by using Pop Greens to grow seaweed like plants to trap the boulders, and when they encountered the New Fish-Man Pirates in the Ryugu Palace, he used a giant flower with a terrible smell to deter them.
In another battle with some of the New Fish-Man Pirate lackeys, Usopp is also seen using a particular type of Pop Green that makes bamboo shoots erupt from the ground, impaling or gouging his enemies. Later, in a fight with Daruma, he shoots a special exploding Pop Green into the tunnels made by Daruma's teeth, which explodes in the shape of a skull. He later uses one that transforms into a giant wolf, with the bulb that it grew from acting as its nose, which releases a stunning shockwave that is 3 meters in diameter to finally defeat Daruma.
During his trip to Green Bit with Robin, Law and Caesar, Usopp's Pop Greens have been shown to be powerful enough to take out a full-grown adult Fighting Fish.
Usopp has also been shown to be able to catch opponents off guard by using the Pop Greens in intricate ways. Also, while Pop Greens are useful for battle purposes, some can also be used for utility functions (likes boats and paddles), as seen in Punk Hazard.
He keeps a small garden on the Thousand Sunny for growing more Pop Greens, in order to maintain a continuous supply of seeds.
↑ 9.09.1One Piece Manga and Anime — Vol. 45Chapter 435 (p. 16-17) and Episode 320, Usopp/Sogeking's bounty for attacking Enies Lobby is revealed along with the other crewmembers'.
↑ 10.010.1One Piece Manga and Anime — Vol. 80Chapter 801 (p. 15-17) and Episode 746, Usopp is given a bounty in Dressrosa with this specific epithet.
↑SBSOne Piece Manga — Vol. 4 (p. 28), Usopp's age is revealed.
500,000,000, being the sixth highest bounty within the Straw Hat Pirates (after Luffy, Zoro, Jinbe, Sanji and Robin). However, rather than being a reflection of his fighting abilities, Usopp's bounty being higher compared to some his crewmates is largely because he always manages to stand out during the major incidents he's been in. At Enies Lobby, Usopp was the one who burned the World Government flag and prevented Spandam from taking Robin past the Bridge of Hesitation with his sniping, earning him (as Sogeking) a bounty of 
