|"There is energy all around us. The energy is both yin and yang; positive energy and negative energy. Only a select few firebenders can separate these energies. This creates an imbalance. The energy wants to restore balance and in a moment the positive and negative energy come crashing back together. You provide release and guidance, creating lightning."|
|— Iroh to Zuko.|
Lightning generation, also known as cold-blooded fire, is a sub-skill within firebending that allows a firebender to produce lightning by separating the positive and negative energies internally, before directing it up through the arm and out the fingertips.
Until at least the end of the Hundred Year War, the ability to generate lightning was an incredibly rare skill, usually reserved for the inner circles of Fire Nation royalty and high-ranking military officers. The only firebenders who had demonstrated the ability to actively generate lightning were Princess Azula, Iroh, and Fire Lord Ozai.
Azula demonstrated the technique while training under the watchful eye of Lo and Li and later when she was fighting her brother, Prince Zuko. Some time later, Zuko expressed a desire to learn this ability as well, though his emotional turmoil prevented him from properly creating lightning.
Ozai was also able to generate a powerful lightning strike with great speed, a skill he used to his advantage against his son during the invasion of the Fire Nation on the Day of Black Sun. He later used it again against Avatar Aang during the presence of Sozin's Comet, though both times, his target redirected the lightning.
While being questioned by Zuko over her conversation with Ozai, a restrained Azula attacked Zuko with lightning, managing to generate the electricity with minimal movement. Later, she also displayed the ability to regulate the voltage of her charge, as she harmlessly zapped Sokka with a lightning bolt as opposed to inflicting lethal damage. As she tried to escape Team Avatar while on their way to Hira'a, Azula used lightning to distract Aang and attack a hallucination of Ursa in a river. When the group was later attacked by spirit moth wasps, Azula was able to charge a large ball of lightning, leading the insects away to follow the light. Impatient with Rafa and Misu's interference of her search for Ursa, she attacked them, though found her lightning intercepted and redirected at the sky by Zuko. After learning her mother's location and new identity, Azula broke into her home by damaging the roof with her lightning. Her subsequent attack was once more thwarted by her brother, however, who sent her lightning back at her.
By 170 AG, the ability to generate lightning had become more widespread, though was still a rare skill. With an increased generation speed, the technique became a coveted skill to be used in Republic City's power plants, where lines of firebenders generated lightning to create electric currents for the city's industrial district.
Lightning Bolt Zolt used this technique in his duel against Amon, generating a continuous stream of lightning. Despite the destructive capabilities of the attack, the Equalist leader emerged victorious and took away Zolt's bending, reducing the stream of electricity to fire and eventually nothing. Mako also used lightning during Team Avatar's conflicts with the Equalists, also displaying the ability to regulate the voltage of his lightning strike, managing to stun the driver of an Equalist truck as opposed to killing him. Despite being held down by Amon's bloodbending, Mako managed to generate a bolt with minimum movement that was powerful enough to fling Amon across the room.
Lightning remained a favored technique of Mako's, as a year later, when a group of dark spirits attempted to reach Korra's body within the Tree of Time, he struck them down with it. Later that year, he used it as a last resort when fighting Ming-Hua in an underground lake, using the water as a conductor and electrocuting her in the process.
In 174 AG, during the invasion of the United Republic of Nations, Mako used his ability to generate lightning to shut down the spirit vine-charged power core of the enormous mecha suit with which Kuvira carried around her spirit energy cannon. By taking the time to truly charge the lightning, he was able to keep up his attack for a prolonged time, though the extended use caused severe burns on his left forearm. Eventually, he managed to overload the energy levels of the power core, causing it to explode.
Generating lightning involves a circular motion with the arms. Mentally, it involves a complete absence of emotion and peace of mind, and physically, it requires separating the energies of yin and yang, also interpreted as positive and negative electric potential respectively. When the yin and yang collide together to become whole again, lightning is created, with the bender only guiding, rather than controlling, the lightning's direction. If one attempts to conjure lightning without the required emotional discipline, it can instead result in a huge explosion of fire.
Because of this complexity, a lightning attack usually takes much longer to initiate than standard fire attacks, though skilled benders, like Ozai, have generated lightning much faster than others less skilled in the art. Mako, however, demonstrated himself to be capable to generate lightning with minimal motion, even while under Amon's bloodbending grip, though it was not lethal. The technique is extremely taxing on a firebender's chi reserves, which is why young men are sought out to work at power plants.
While lightning is generally fired as a single strike, it can also be sustained or shot in a continuous bolt and held until the user stops producing it. During this time, the lightning can be swept about to produce widespread damage.
Based on the conclusion of the Coup of Ba Sing Se and its aftermath, it appears that if it is not blocked or redirected in some way, a lightning blast will be fatal to any human being, although Amon was shot with lightning and was able to survive. The generation technique cannot be used to defend against lightning; knowledge of a separate technique, lightning redirection, is required.
Zuko and Aang both survived Azula's lightning strikes due to Katara's healing abilities. Aang was resurrected by the spirit water after being fatally wounded, while Zuko had to be healed after hurriedly redirecting a lightning bolt Azula fired at Katara. While he was successful in redirecting much of the lightning, his state afterward suggested that Zuko did not have time to finish the move, resulting in some of the energy remaining in his body. This left him incapacitated and unable to keep fighting Azula.
Even in cases where a person survives a strike, it seems they will still be critically wounded: Aang's wound was still raw, to the point where it still bled, and debilitating over a month after he sustained it, and had not completely healed by the end of the War. Zuko's was apparently still raw and painful by the time of his coronation, even though Katara had healed him shortly after he sustained the wound.
The charge, and thus the damage, of a lightning strike can be regulated. During his fight with Amon, Mako was able to control the charge of his lightning, firing a bolt strong enough to incapacitate, but otherwise not harm, his opponent, as Amon quickly recovered from the blast.
While the generation of lightning can be maintained for extended periods, the continued and excessive use can lead to burns.
- The movements involving lightning generation are drawn from a form of Shaolin martial arts known as "Dragon Shoots Its Whiskers".
- Lightning generation was referred to by Avatar Extras as "lightning bending".
- Mako has used lightning generation in the finale of each book of The Legend of Korra.