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. In this form, Sanji, due to the high temperature, has the ability to burn his opponents. While like this, he can light his opponent on fire. Sanji can also utilize this 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 an ordinary human being. Given that his Raid Suit-induced powers enable invisibility, it does not appear that the ability to ignite himself is a result of his father's modifications.

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, 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 does a running jump and kicks with both legs into an opponent's stomach rapidly various times, but Diable Jambe's heat greatly increases the power. This was first seen being used against Jabra. Unfortunately for Sanji, it missed. This is called Premiere Hache in the Funimation dub, and in the Viz Manga, this is called Premier Hachisash.
 * 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): In the air (sometimes several feet from the ground), Sanji kicks the side of an opponent with his foot and 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 Franpage Shot in the Funimation dub of One Piece: Unlimited Adventure but retains its original name in the Funimation dub. In the Viz Manga and Funimation subs, this is called Flambé Shot.


 * 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 make it look like one big fire blast. This was first used against Moria in an attempt to retrieve Robin's shadow.




 * Frites Assorties: A completely 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 in Diable Jambe mode, 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 a Mouton Shot in Diable Jambe mode. 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
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 leg(s) to perform Diable Jambe and thus is no longer dependent on spinning to do so, even capable of igniting his leg underwater. This new ability is somehow tied to the trauma Sanji endured for the last 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 from the fact that when activated, it seems more shiny, with a cross of light (similar to when Kizaru or Pacifistas charge their laser beams) on the tiptoe. As shown in his fight against Doflamingo, Sanji can now activate Diable Jambe in both legs simultaneously. It also seems that Sanji can now utilize more new 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 will spin around slightly and deliver a strong back kick to the center of his target. This will burn a significant amount of the target (considering that it was used underwater, several thousand meters down) around the kicked area and leave a crisscrossed grill shaped burn. This 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 left leg instead of having his right leg in flames and delivering a front kick with his right leg. In the Funimation subs and Funimation dub, it is called Bien Cuit Grill Shoot.




 * 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 be the reason why Sanji decided to put the "Spectre" word (which is French for Spectrum) in the name of this attack. This technique seems to be an enhanced version of Diable Jambe: Extra Hachis, as Sanji kicks only with his flaming leg, not with the other. It was first seen being used against several New Fishman Pirates. In the anime, the kicks appear to launch fireballs and create rainbow rings when they burst the mermen's bubbles. In the Funimation versions, this is called Poele a Friere: Spectre. In the Viz Manga, this is called Poilu au Frille - Spectre.




 * Collier Strike (ストライク): This technique is a new version of Collier Shoot, but now combined with Diable Jambe. Sanji jumps into the air, appearing in front of his opponent and then lands a devastating kick to their 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 Flanchet Shoot, Sanji delivers a kick to the opponent's stomach. In the Funimation dub, this is called Flanchet Full Power Strike. This was first used to send Vergo flying into a wall.


 * Joue Shoot (シュート): 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.




 * 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.


 * 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 french for "butt", that comes from "crosse de porc", pork 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, stands over his hands and spins delivering multiple flaming kicks. Like his normal version, this is a very useful move for large groups of enemies. It was first used on several Beasts Pirates to clear Luffy's path on his way to fight Kaido 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 prostethic needle-like fangs. Rotisserie is a style of roasting also known as "spit-roasting".

Trivia

 * Diable means "Devil" in French and Catalan, and Jambe means "leg" in French. 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.