Nico Robin has a lot of unrealized potential in the One Piece series, particularly in her fighting style.
She definitely lacks in dedicated fights compared to other Straw Hats, but she makes up for it with her creative Devil Fruit powers. The Hana Hana no Mi allows her to duplicate body parts anywhere she wants, so Robin has always had the element of surprise with her attacks.
However, the main weakness of her fruit is that any damage to replicated limbs will also be felt by her. Her abilities don't make her invincible by any means.
Win or lose, Robin will always be a dangerous fighter in One Piece.
One Piece characters that Nico Robin would win against
Nami has mastered the ability to manipulate weather attacks. Her Sorcery Clima-Tact is a versatile weapon used for offensive and defensive purposes. Nami can also rely on Zeus for his powerful lightning attacks.
However, none of that matters since Robin could easily capture Nami right away. She could use her various Clutch techniques to sprout arms from anywhere.
Nami does not have the reaction time to dodge it since it can be done instantly. All Robin has to do is disarm Nami's weapon, and the battle is over.
3) Miss Doublefinger
At first glance, the Hana Hana no Mi should be an awful match-up against the Toge Toge no Mi. Miss Doublefinger has the ability to grow pointed spikes anywhere on her body.
Robin could easily get stabbed if she is not careful with her attacks, but she does have a trick up her sleeve. Since the One Piece timeskip, Robin has mastered Fishman Karate under the Revolutionaries.
Miss Doublefinger isn't remarkably durable, so Robin could try knocking her out with a surprise palm attack. The latter can also sprout gigantic limbs, giving her more attacking power and distance.
From what little is seen from her, Koala is quite proficient with Fishman Karate. She was able to defeat several men in the Dressrosa arc by herself. Koala is also a very agile fighter that can strike opponents when they least expect it.
With that said, Robin has far more range with her attacks. Koala can try dodging them, but she can't predict every movement. Robin can attack from anywhere and anytime with her Hana Hana no Mi. The Revolutionary would likely be overwhelmed by a direct encounter.
The Straw Hat fanboy is exceptionally powerful for a pirate rookie. During the Dressrosa tournament, Bartolomeo was the B Block winner thanks to his Bari Bari no Mi. Its defensive nature can withstand the most potent attacks, such as a King Punch from Elizabello II.
However, Bartolomeo can only put up a single barrier at any given time. Since Robin can sprout limbs on any surface, she can bypass the barrier easily. She is a very dirty fighter in One Piece, so Robin can bring him down to his knees with her infamous Grab technique.
One Piece characters that Nico Robin would lose to
Before the One Piece timeskip, Nico Robin could easily manhandle Franky by playing dirty. However, the latter spent two years studying Vegapunk's futuristic designs, so his BF-37 form is far more resistant now.
Robin doesn't really use Haki, so it will be challenging for her to bypass Franky's durability. Her approach is very limited in this fight.
He might be relatively slow, but his Radical Beams cause massive explosions. It also reaches breakneck speeds and can destroy multiple Pacifistas, as seen in One Piece Film: Z. A single hit from this attack would likely incapacitate Robin.
3) Rob Lucci
Two years after the events of Enies Lobby, Robin has become a much better combatant. Her fighting style is complemented by her skilled usage of Fishman Karate. She could land multiple strikes with power and precision. However, it's still not enough against Rob Lucci.
He was already the strongest member of CP9. Now he is a member of CP0, the most potent organization under Cipher Pol. Lucci has definitely grown ever since the One Piece timeskip, so he wasn't slacking off like Buggy and Arlong.
Robin may have mastered the basics of Fishman Karate, yet, Lucci is far more skilled with his Rokushiki. That's not even getting to his massive endurance via the Neko Neko no Mi, Model: Leopard. Robin will not get past a bloodthirsty Lucci, especially in his Zoan state.
Unfortunately, Robin's lack of Haki expertise puts her at a significant disadvantage against Logia users. Her former Baroque Works boss has fully mastered the Suna Suna no Mi, which lets him turn into sand.
Crocodile reflexively dodged attacks from Doflamingo back in Marineford. There is no way that Robin would catch him off guard. Without the use of water or Armament Haki, she cannot touch him.
Meanwhile, the One Piece villain has several long-range attacks at his disposal. Desert Grande Espada can easily cut her in half, as seen when the attack hit Akainu in Marineford despite his enhanced reaction time.
1) Kuzan (Aokiji)
This seems pretty obvious, given that Kuzan is among the strongest Marines in the One Piece series. He can become a freezing human with the Hie Hie no Mi, which gives him control over the battlefield.
However, that is not why Robin would lose this match-up. The reality is that she would likely suffer from mental trauma. Several years ago, she barely survived the Buster Call on Ohara. Her friend Jaguar D. Saul saved her life, but not before he sacrificed himself against Kuzan.
The former Admiral is among the few characters who can strike fear into Robin. Keep in mind that she rarely gets alarmed in the One Piece series.
Even if she had the strength to fight Kuzan, she wouldn't be in the right state of mind. Regardless of her power level, Robin has already lost half the battle here.
Note: This article reflects the writer's personal views.