Black Leg Style/Diable Jambe

Diable Jambe is the latest addition to Sanji's original fighting style, where he 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. It is also later revealed that Sanji can utilize this with either his left or right leg.

Before the Timeskip
Before the 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 (一級挽き肉（プルミエールアッシ）): 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 Hachis in the FUNimation dub, and in the Viz Manga, this is called Premier Hachisash.


 * Flambage Shot (画竜点睛（フランバージュ）ショット): In the air (sometimes several feet from the ground), Sanji kicks the side of an opponent's head with his foot (or the middle of their torso) 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, but had to use the other leg to deflect half of Jabra's Jushigan, in order to "reserve" his flaming leg for the finishing blow. This is called Franpage Shot in the FUNimation dub, and in the Viz Manga and FUNimation subs, this is called Flambé Shot.


 * Extra Hachis (最上級挽き肉（エクストラ・アッシ）): 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 makes it look like one big fire blast. This was first used against Moria in an attempt to retrieve Robin's shadow.


 * Frit Assorti (揚げ物盛り合わせ（フリットアソルティ）): A completely revamped version of the original Frit Assorti. 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, apparently powerful enough to deflect Oars' Gomu Gomu no Bazooka attack.


 * Mouton Shot (羊肉（ムートン）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 Hou.)


 * Venaison Shoot (野獣肉（ヴネゾン）シュート): Sanji, spinning horizontally in the air, kicks the opponent repeatedly in the chest and belly, finishing the attack with a powerful axe kick on the head with the speed, heat and strength of the Diable Jambe mode. This was first seen being used to defeat Scarlet during the events of One Piece Film: Strong World.

Team Combination

 * Santoryu Gomu Gomu no Diable Mouton Jet Roppyaku Pondo Cannon (三刀流ゴムゴムの悪魔風羊肉JET六百煩悩攻城砲): A combo attack performed by all three top fighting members of the Straw Hat Crew: Zoro, Luffy and Sanji. Zoro performs a 108 Pound Hō, while Sanji activates his Diable Jambe technique and delivers a Mouton Shoot, then Luffy uses Gear Second and fires a Gomu Gomu no Jet Cannon. The impact of the three techniques hits a single target simultaneously. This was first seen being used against PX-4. In the FUNimation subs, this is called Santoryu Gum-Gum Diable Mouton Jet 600-Caliber Phoenix.

After Timeskip
After two years of training in the Kambakka Kingdom, Sanji demonstrates a far better mastery of Diable Jambe able to use it frequently without any adverse effects.

The manga also shows that Sanji is now able to activate Diable Jambe in an instant and thus is no longer dependent on spinning to do so, even capable of igniting his leg underwater. This is partially due to the trauma Sanji endured for the last two years, so much so that simply reminding himself of it causes him to burst out in flames through sheer anger.

However the anime contradicts this information by showing Sanji to be still dependent on spinning, albeit much less spinning than was required pre-timeskip. Seeing as the manga is official canon, this contradiction is most likely a mistake of the anime.

The improved version of Diable Jambe, in comparison with it's 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. 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 (熟焼（ビアン・キュイ） 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 attack seems to be an enhanced version of Diable Jambe: Mouton Shot. 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, it is called Bien Cuit Grill Shoot.


 * Poêle à Frire: Spectre (焼鉄鍋（ポアル・ア・フリール） 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.


 * Collier Strike (首肉（コリエ）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.

Trivia

 * Diable Jambe is probably a reference to the "sauce à la diable", a French spicy sauce.
 * A "diable" is also an earthen kitchen utensil used for baking food.
 * When using Diable Jambe, Sanji assumes a stance and fights similar to the fighting style Muay Thai, which relies on strong direct kicks.