The Bari Bari no Mi is a Paramecia-class Devil Fruit that allows the user to generate barriers for defending or striking at will, turning the user into a Barrier Human (バリア人間,Baria Ningen?).Bari comes from baria, the Japanese way of pronouncing the word "barrier". It was eaten by Bartolomeo.
The main strength of this fruit is that it allows the user to form invisible barriers, though they can be solidified to become visibly transparent, resembling a pane of glass. This protects the user from attacks from either front or back. The barriers appear to be immovable by any outside force. The barriers are strong enough to defend against even a fishman'shigh-powered punch, which injured said fishman's hand in return. Even the shock wave produced from Elizabello II's punch, which could allegedly take down an entire fortress, could not breach the shield, nor the area behind it. The shield can also be used for offensive purposes by launching it forward to create powerful forces to strike the targets, or to deflect forces sent by enemies right back at them. According to Bartolomeo, he can create his barriers by crossing his fingers.
Another strength of this fruit is that Bartolomeo can form solid constructs out of his barriers, such as stairs which people can stand on, making this fruit useful for getting to hard-to-reach places.
It is unknown if the barriers have a damage limit, but so far the ability appears to react depending on the strength of incoming force, as Bellamy was able to injure Bartolomeo with an outstretched hand, rather than with a strike, Additionally, with the barrier reacting to Hack's punch while Bartolomeo wasn't facing him, this may indicate it being a passively-active fruit. Bartolomeo has also stated that the barriers are not soundproof. An additional limitation is that there is a maximum total surface area of any barrier(s) that Bartolomeo can produce at one time; examples of this include being unable to completely block Pica's giant stone fist, as well as being incapable of producing more barriers after crafting a staircase out of them. Besides these weaknesses, it shares the standard weaknesses of Devil Fruits.
Bartolomeo uses the fruit's power to protect himself in combat, sitting idly by while his unsuspecting foes attack him and injure themselves. He can also use the shields offensively to strike down and repel his targets. He can also use the barriers as walls to immobilize and crush his victims.
Barrier (バリア,Baria?): Bartolomeo activates his fruit's ability by crossing his fingers, causing a transparent barrier to appear which can protect him from attacks. So far, two shapes for his barrier have been seen, a rectangular barrier and a semi-spherical barrier.
Barrier Crash (バリアクラッシュ,Baria Kurasshu?): Bartolomeo forms a transparent barrier in front of himself and sends it towards the enemy so fast it crushes his enemy. The crush is powerful enough to defeat Elizabello II and create a shock wave. It was first shown being used against Elizabello in Corrida Colosseum right after it shielded Bartolomeo from the King Punch. He showed what appears to be a variation of this technique earlier, kicking Hack with an invisible force boosting the strike.
Barrierbility: Stairs (流動防壁（バリアビリティ） 階段（ステアーズ）,Bariabiriti: Suteāzu?, literally meaning "Flux Barrier: Stairs"): Bartolomeo activates his fruit's ability by squeezing his hands while crossing his fingers. He changes the shape of his barriers into a flight of stairs, allowing him or his allies to move freely in the air while protecting them from attacks coming from below. It was first shown being used to help Luffy and Law reach the fourth level of the King's Plateau.
It can be considered ironic that Bartolomeo has this Devil Fruit because while his behavior is generally provoking, this Devil Fruit is defensive by nature.
The sign Bartolomeo performs with his fingers when summoning his barrier is commonly known in Japan as either to repel "bad things" or provoke others by saying they are being repelled as they said "bad things".