Black Leg Style/Diable Jambe

Diable Jambe is a technique where Sanji heats up his leg, adding extreme heat to the impact of his kicks. While doing so, Sanji has the ability to burn his opponents or light them on fire due to the high temperature. Sanji can utilize this technique with either his left or right leg, as well as both at the same time.

According to Sanji, he can perform Diable Jambe because of his "burning passion", though whether this is a serious explanation remains to be seen. The ability is rare enough to make Queen speculate it is only possible with some kind of genetic enhancement, assuming he is not of the Lunarian race, but Sanji denied that this is the case and stated he is a regular human being. Given that his Raid Suit-induced his powers to enable invisibility, it is unknown if  the ability to ignite himself is a result of his father's modifications as well.

Before the Timeskip
Before the timeskip, Sanji would activate Diable Jambe by spinning at high speeds, thus heating up his leg due to friction. This technique has been shown to have adverse effects, and if Sanji uses it for too long or too frequently, he could cause serious injury to his body. Below is the list of techniques that Sanji utilized when Diable Jambe was activated.


 * Premier Hachis: Sanji performs a running jump and rapidly kicks with both legs into an opponent's stomach multiple times, with Diable Jambe's heat greatly increasing the power. This was first seen being used against Jabra. Unfortunately for Sanji, it missed. This is called Premier Hachisash in the VIZ manga and Premiere Hache in the Funimation dub.
 * This is the first of Sanji's old techniques used after the timeskip. Any differences between the pre-timeskip and post-timeskip versions are unknown, as Donquixote Doflamingo dodged the attack when Sanji attempted to use it.




 * Flambage Shot (ショット): While in the air, Sanji kicks the side of an opponent with his foot as Diable Jambe's heat greatly increases the power, often with explosive effect. The target is usually kicked downwards, causing them to come crashing into the ground. This was first seen being used to finish off Jabra, though he had to use the other leg to deflect half of Jabra's Jushigan in order to "reserve" his flaming leg for the finishing blow. Flambage is the French word for "flambé", a cooking procedure in which alcohol is added to a hot pan to create a burst of flames. This is called Flambé Shot in the VIZ manga and the Funimation adaptations, but is called Franpage Shot in the Funimation dub of One Piece: Unlimited Adventure.


 * Extra Hachis: Sanji leaps into the air and launches a fierce barrage of flaming kicks, the light from the attack and the speed at which it is delivered making it look like one large fire blast. This was first used against Moria in an attempt to retrieve Robin's shadow.




 * Frites Assorties: A revamped version of the original Frites Assorties. Jumping high into the air, Sanji delivers three simultaneous kicks in three directions (left, right, and forward) while Diable Jambe is activated, resulting in flames spiraling towards the target at the point of impact. It was first used to deflect Oars' Gomu Gomu no Bazooka attack.


 * Diable Mouton Shot (ショット): Sanji performs an anhanced version of the original Mouton Shot with Diable Jambe activated. This was first seen being performed for a three-way team combo, the Santoryu Gomu Gomu no Diable Mouton Jet Roppyaku Pound Cannon (along with Luffy's Gomu Gomu no Jet Cannon and Zoro's 108 Pound Ho). This is the only Diable Jambe attack that does not contain "Diable Jambe" in its name, only "Diable".
 * This is the second of Sanji's old techniques used after the timeskip, with the effects remaining the same. It was used to knock out Sheepshead. After the timeskip, this is called Diable Mouton Mallet in the VIZ manga.

After the Timeskip
After two years of training in the Kamabakka Kingdom, Sanji demonstrates a far better mastery of Diable Jambe, using it frequently without any adverse effects. He also appears to replace the "shoot" in his attack names with "strike".

Sanji is now able to spontaneously ignite his legs to perform Diable Jambe and is no longer dependent on spinning to do so. He is even capable of igniting his leg underwater. This new ability is somehow tied to the trauma Sanji endured over the course of the two years, the memory of which seemingly causes him to burst out in flames through sheer anger. Sanji's new Diable Jamble is even strong enough to clash with his father's advanced technology. It was later shown to be strong enough to briefly knock out Monkey D. Luffy, despite the latter's rubber body.

The improved version of Diable Jambe, in comparison with its pre-timeskip version, also differs in that it seems brighter when activated, with a flash of light at the toe. As shown in his fight against Doflamingo, Sanji can now activate Diable Jambe in both legs simultaneously. Sanji can now utilize new, more powerful attacks with his Diable Jambe. They are listed as follows.




 * Bien Cuit: Grill Shot (グリル・ショット): A new technique learned after two years of training in Kamabakka Kingdom. Running at his target at incredible speeds (if done underwater, after using Blue Walk), Sanji spins around and delivers a strong back kick to the center of his target. This will burn a significant portion of the target around the kicked area and leave a grill-shaped burn. This attack was first seen underwater against one of the Kraken's tentacles. This move is changed in the anime, where Sanji delivers a back kick with his before delivering a front kick with his right leg. Bien cuit is the French term for "well-done".. This is called Bien Cuit Grill Shoot in the VIZ manga and the Funimation adaptations.




 * Poêle à Frire: Spectre (スペクトル): Another new technique learned after two years of training in Kamabakka Kingdom. After using Sky Walk, Sanji kicks repeatedly downward with his flaming leg to take out multiple opponents. The way Sanji moves his flaming leg is very similar to the way Ivankov moves his head while using Ganmen Spectrum, which seems to explain why Spectre (which is French for "spectrum") is in the attack's name. It was first seen being used against several New Fish-Man Pirates. In the anime, the kicks appear to launch fireballs and create rainbow rings when they burst the mermen's bubbles. Poêle à frire is the French word for "frying pan". This is called Poilu au Frille - Spectre in the VIZ manga and Poele a Friere: Spectre in the Funimation adaptations.




 * Collier Strike (ストライク): An enhanced version of the original Collier Shoot attack. Sanji jumps into the air and delivers a devastating kick to the opponent's neck. This kick is not only strong enough to send the opponent flying while burning them, but also releases a small stream of fire that pierces through the opponent's body. This move was first seen used against some pursuers on Punk Hazard.


 * Flanchet Strike (ストライク): An enhanced version of the original Flanchet Shoot attack in which Sanji delivers a kick to the opponent's stomach. This was first used to send Vergo flying into a wall. This is called Flanche Strike in the VIZ manga and Flanchet Full Power Strike in the Funimation dub.


 * Joue Shoot (シュート): The Diable Jambe version of his normal Joue Shoot attack. Sanji races toward his opponent, keeping his burning leg off the ground. He then leaps up and kicks his opponent square in the face. This was first used against Monkey D. Luffy, and was powerful enough to send Luffy flying a considerable distance back. In the VIZ manga and the Funimation dub, this is called Joue Shot.




 * Concassé: The Diable Jambe version of his normal Concassé attack. Sanji uses Sky Walk to get high up in the air before tumbling down with his leg outstretched, gaining speed by spinning. He then slams his heel on the top of their head. This was first used against Luffy, and succeeded in briefly knocking him out. In the VIZ manga and Funimation adaptations, this is called Concasse.


 * Crosse Strike (ストライク): Sanji delivers a powerful flaming front kick. It was first used along with Luffy's Elephant Gun during their attempt to save Reiju, blocking Big Mom's lightning attack. Crosse is the French word for "butt".


 * Party Table Kick Course (パーティーテーブルキックコース): The Diable Jambe version of his normal Party Table Kick Course attack. Sanji heats both of his legs up before performing a handstand and spinning to deliver multiple flaming kicks. Like his original version, this move is used to target large groups of enemies. It was first used on several Beasts Pirates to clear Luffy's path on his way to fight Kaidou during the raid on Onigashima.




 * Rotisserie Strike (ストライク): Sanji delivers a flaming kick that causes the opponent to spin rapidly before slamming into their surroundings. This was first used against Queen in his Brachiosaurus form, causing his long neck to spin and deflect Perospero's candy arrows. The attack was strong enough to shatter Queen's prosthetic needle-like fangs. Rotisserie is a style of roasting also known as "spit-roasting".

Trivia

 * In French and Catalan, Diable means "Devil" and Jambe means "leg". This probably comes from à la Diable, a term used for spicy recipes in French cuisine.
 * When using Diable Jambe, Sanji assumes a stance and fights similar to the fighting style Muay Thai, which relies on strong direct kicks.
 * When asked why Sanji's Diable Jamble does not burn him as well in SBS, Oda claimed while Sanji's flames burn hot, his heart burns hotter.