Sword of Fire
- “As long as there's something worth fighting for, there's always a need for a Ninja. And we'll be ready!”
- ―Kai at the end of "Rise of the Spinjitzu Master"
Kai is the red ninja of fire minifigure released in 2011 as part of the Ninjago theme. Sensei Wu entrusted the map to the golden weapons to Kai's father. Kai is the Ninja of Fire and the strongest of the four and is also the brother of Nya. He was a 'blacksmith' before apprenticing himself to Sensei Wu to save his sister Nya. Kai is fiery in both fighting style and temper, and a very independent character. However, he eventually gained control over his impulsive tendencies.
Kai, like the other ninja, has several different variations.
Regular 2011 Variant
Kai's original costume, which appeared in several sets in 2011, is almost entirely red. His legs are red, printed with a dark red sash, which is also printed on his hips. His torso is also red, with black hands. It is printed with several dark red sashes, which are connected to a gold badge, that looks rather like a lion. His face is yellow, and shows a determined expression. It has several red scars running across it. He wears a red ninja wrap.
Kai's DX variant is, fairly similar to his regular version, but with notably different printing. The DX version's lower section, like those of the regular one, are printed with a sash on the legs and hip, but, unlike its predecessor, it has a fiery dragon tail printed on it. The torso is pure red, with black hands, and a fiery dragon printed on it in gold. On the back of the torso, is printed Kai's name. The face and wrap used on the variation are identical to those used previously.
This version of Kai, first introduced in 2012, has Kai's basic legs-that is, red, printed with a sash. The torso has black hands, and is covered with kendo armour, but, underneath, is exactly the same as that used by Kai's basic variant in 2011. His head is, again, the same that is used by his basic variant, but, instead of a ninja wrap, he wears a kendo helmet, which bears a distinct resemblance to a grilled hockey mask.
Kai's ZX variant has red legs printed with the bottom of a tunic, and a red torso (with dark red arms and black hands), printed with a tunic, dark red armour, and a dark red belt (with an unidentified silver tool in it). He wears around his neck a sheath-like object, which katanas can be stuck into. His face is he same as that used in all his prior variations, but his wrap is notably different, as it has a large gold ornament attached to it's front.
Another version of the ZX suit is available, that has a large jetpack attached to it's back in place of the scabbard.
NRG Kai has red legs, a red torso with a large explosion printed on it, and a red face with a rather demonic expression. His wrap is similar to the one used by his ZX form, but has a thinner ornament that resembles fire.
Kai obtains the Techno Robes from Cyrus Borg in order to block the facial recognition system the Overlord has on his robots. Unlike the previous variants, it is only a half-mask and reveals his hair. It appears in the sets 70721 Kai Fighter and 70727 X-1 Ninja Charger.
As a Microfigure, Kai is exclusive to the set 3856 Ninjago. He is composed of a single red piece, which is moulded with bumps to represent arms and legs, and printed with his red clothes, a gold badge, and a sash, as well as the small portion of his face visible under his wrap.
As an alarm clock (the set 9003097 Kai Minifigure Clock), Kai is very similar to his basic form from 2011, but he is considerable larger, made out of a single part (although his limbs can be moved), and has a digital clock-face in his chest.
Kai as a blacksmith only appears in the televised version of Ninjago,Set The Four Weapons Blacksmith Shop from 2011, and in LEGO Battles: Ninjago. He has fairly basic legs, a white torso printed with a heavy-duty apron, his basic face, and in the video game, brown Exo-Force hair.
Kai's original variation was a basic "ninja suit". It has no special powers, and was given to him by Sensei Wu. His second variation, his DX version, was a special suit, received after he has met his dragon, and found the Sword of Fire. His kendo variation, used after that, was his regular variation, but with extra armour, for use in training. His ZX version arrived mysteriously in the mail, and is an upgraded version of his regular suit. In the episode "The Green Ninja" Kai unlocked his full potential and turned into his NRG variant by saving Lloyd Garmadon in the Fire Temple instead of getting the fangblade. His Elemental Robe was unlocked when the ninja made it to the Temple of Light and Lloyd struck the "instrument of peace".
Before the Ninja
- “It's called Four Weapons, not For Browsing. So either buy something, or go peddle your insults someplace else!”
- ―Kai to Sensei Wu before becoming a ninja
Introduction to Spinjitzu
Once, when Kai and his sister, Nya were working the Four Weapons blacksmith shop, they were approached by Sensei Wu, who showed disdain for the weapons they made, claiming that they would be useless in the art of stealth. He also said that they were fit weapons for a samurai, but useless for a ninja. Kai drove him off, but he then disappeared when Kai turned his back. Moments later, a dark cloud appeared over the village, which local farmers were the first to notice. On the edge of a hill, a large vehicle (the Skull Truck) appeared along with many motorcycles, all with skullkin aboard them, notably General Nuckal, Kruncha, and Samukai. The farmers attempted to attack the skullkins, only to run away at the last second. Then, Kai, wearing hand-crafted samurai armour, helmet, and sword, engaged the skullkin in battle, with Nya joining in. Kai was nearly killed by Samukai, only to be saved by Sensei Wu, who reappeared just in time. He was not able to save Nya, who was kidnapped under the orders of Lord Garmadon. Sensei then told Kai the history of Ninjago.
After telling Kai the story, Sensei told Kai that his father had a map made by Wu, showing the locations of the hidden Golden Weapons, and also that Garmadon had struck a deal with Samukai, and that Wu was Garmadon's younger brother. Kai at first refused to get involved, until realizing he wouldn't stand a chance against the skullkin on his own.
He then trained in Wu's monastery, and, after completing his training, awaited a final test, but is told he had already learned spinjitzu.
Later that night, Kai was ambushed by three ninjas, and the ensuing battle causes him to be thrown out onto the training grounds. Kai activated the training course and the obstacles disarmed his attackers. Moments later, Sensei Wu stops the fight, revealing that the three are his other students. Sensei then uses spinjitzu to transform their black costumes into outfits corresponding with their element. The four are introduced to each other: Cole, the black ninja of earth; Jay, the blue ninja of lightning; Zane, the white ninja of ice and a seer with sixth sense; and Kai, the red ninja of fire. Introductions were cut short as Wu announced the search for the golden weapons had now begun.
The Search for The Golden Weapons
- “Watch out evil. I burn.”
Their first destination of the ninja was the Caves of Despair, where the Scythe of Quakes was hidden. Here, Kai raced off in hopes of finding his sister. Instead, he nearly was caught by the skullkin Krazi, who would have raised the alarm, but the other ninja got there in time, and shoved his Bone weapon into his mouth. As the four captured the Scythe, they were attacked by Samukai and a whole legion of skullkin. Jay noticed that the enemies were just like the training course, and after going through the motions Wu taught him, he summoned a tornado of energy corresponding with his element, lightning. In so doing, he performed spinjitzu, and was quickly copied by the others. Samukai and his legion retreated, as they saw the Earth Dragon, guardian of the Scythe appear behind the ninja. In desperation, Kai used the scythe, despite Wu's instruction not to use the weapon's power, as no mortal could handle it. A rift appeared in the cave ceiling, and the ninja managed to escape. Wu became quite angry at Kai for using the weapon's power.
As the ninja were aboard a boat, sailing to reach the desolate frozen planes in which the Shurikens of Ice were to be found, Wu taught them the most powerful move in spinjitzu: the Tornado of Creation.
The boat arrived at it's destination, crashing into the island, and the ninjas entered the frozen plains. The group yet again escape a dragon guarding the weapons, and, as Zane was frozen upon contact with the shurikens, the others used him as a snowboard.
With the shurikens being in their possession, they continued on. At the Floating Ruins, they climbed a giant chain to the Nunchucks of lightning, retrieving them, but being forced to jump off of it to escape the lightning dragon. The four survive this experience because of special inventions made by Jay, backpacks that spawn wings.
The ninja were at such a high altitude when they jumped, that they were able to fly to all the way to the Forest of Tranquility, the location of the Sword of Fire. After a long day's work, everyone fell asleep. Kai was then awoken by none other than Nya. She ran away, and Kai chased her through the forest, eventually entering the Fire Temple.Nya was then revealed to be an illusion created by Lord Garmadon to lure Kai there. He exploits the fact that Kai had forgotten his sword, and that the real Nya is hanging from chains above a pit of lava. Garmadon tells him the only way to save Nya is to pull the Sword of Fire out of the rock it is stuck in. Kai obtains the sword, cuts Nya free, and was then confronted by solid shadows. Wu arrived, and attempted to take them out, but then the Fire Dragon appeared. Sensei decided to make a sacrifice, and jumped on a rock that was headed down a lava fall so he may bring the sword to the Underworld. Kai tried to ask Sensei if there was another way, and blamed himself for going after Nya alone, but was is too late-Wu was in the Underworld.
Battle with Lord Garmadon
- “You thought I was hot before. Well now I got a dragon, and I'm really on fire!”
- ―Kai DX
Awakening of the Serpentine
After a long period in inactivity following Garmadon's escape, Kai and the other ninja went to investigate a report of his return. They went to Jamonicia village and see Lloyd Garmadon, his son, terrorizing the villagers. After the ninja defeated him and left him to the villagers, Kai found a scroll telling of the coming of the mysterious Green Ninja, the most powerful ninja of all. He asks himself if it is possible that he will become him. To determine, he challenges the other ninja to a fight. After beating Jay, he faced off against Cole, during which his sword nearly burned down the entire monastery. Afterwords, Sensei Wu announced that the the Serpentine, an ancient and dangerous race of snake people are back, and are terrorizing Jamonicia village. The ninja return there, and encounter the Hypnobrai tribe of Serpentine, who have been awakened by Lloyd. Kai's appearance in this battle is limited, and shows that his Spinjitzu is too unstable to control. After the battle, he asks Sensei Wu to teach all of them the secrets of the golden weapons.
Afterwards, he and the other ninjas made fun of Zane for his odd behavior. Zane then discovered Lloyd Garmadon's tree-house, and lead the other ninja their. After Cole, who was hypnotized by Skales of the Hypnobrai, is pitched against the others, Kai refuses to use his sword in fear of destroying the entire place. After Sensei Wu un-entrances him, they return to see the monastery in flames. Kai is the first to turn on Zane. After Zane flies off, Kai and the other ninja take shelter, and then see Zane approaching them. After he explains that he flew off to see his falcon, he leads them to their new home, the ship Destiny's Bounty.
Later, on the ship, Jay's parents, Ed and Edna Walker, come to visit. Jay manages to get them to leave, but promises to visit them at their junkyard the next day. He and the other ninja then go there, only to find the place overrun with members of the Fangpyre tribe, another breed of Serpentine, once again awoken by Lloyd. Kai and the other ninja defeat the Fangpyre, and Nya creates an anti-venom to their poison.
During training a day or so later, Sensei Wu asks the ninja a riddle: "What is the best way to defeat an enemy?" Kai answers "to train", but is incorrect. Later, the ninja discover that Lloyd, with the aid of the Serpentine Pythor P. Chumsworth, have taken over the Boarding School for Bad Boys, from which Lloyd was expelled. The ninja arrive at the school, and rescue the captured students. The ninja corner Pythor and Lloyd on the roof, and Pythor steals Lloyd's map (which shows the locations of the other tribe's tombs), and escapes, leaving Lloyd to the ninja. Later that night, after Lloyd has fallen asleep, Sensei revealed that the answer to his riddle was "To make them your friend".
At Sensei Wu's orders, Lloyd played various tricks on the ninja, one of which mixed up Kai and Zane's uniforms in the laundry, turning Zane's pink. Shortly after this, Nya discovered and revealed the location of the tombs of the Constrictai and Venomari. The ninja split into two teams, Kai and Jay teamed up to find the Venomari Tomb, and Zane teamed up with Cole to find that of the Constrictai. On their mission, Kai and Jay were attacked by Pythor and the Venomari (The Venomari spit venom into his eyes not only making him a bit Waco., but also makes him see what he fears: elves, and gingerbread people), but were saved by Samurai X, who then drugged them with knock-out gas. 
To stop the Serpentine tribes uniting, the ninja traveled to Ninjago city, where the Serpentine had gone. However, they were all captured except Zane, who later freed them, and used the Shurikens of Ice to help them escape.
Later, Kai is forced to baby-sit Lloyd. Determined to find out the identity of the samurai, he leaves him at an arcade. Later, back at Destiny's Bounty, Sensei Wu asks where Lloyd is, and Kai realises that he is missing. He and the other ninja are then sent to find him.
They discover his tracks sometime later, and, by following them, find the city of Ouroborous, where Pythor has just taken over the tribes of Serpentine. Naturally, the ninja try to rescue Lloyd, but are captured, and forced to fight Samurai X. After a long fight, the ninja and the samurai agree to work together to escape. The samurai uses the rockets in her mech-suit to escape, and the ninja grab on, and are flown to safety. However, after they have been dropped off, the mech-suit malfunctions, and falls to the ground. Kai, who was separated from the rest of the group, went to investigate, and discovered that the samurai was none other than Nya. However, Nya swears him to secrecy, asking him not to tell anyone the truth about her.
The Great Devourer
In the course of a battle against the Treehorns, Zane discovers that he is a robot, and unlocks his full potential, becoming an NRG ninja. The same day, Sensei Wu tells a story of The Great Devourer, a giant evil snake, and how its venom corrupted Lord Garmadon when he was young. Wu then leaves the ninja to find Garmadon. Later Kai discovered his full potential when he saved Lloyd Garmadon instead of going after the fang blade.
Back in Time
Once taking the golden weapons, Lord Garmadon goes to the Golden Peaks, the birthplace of the golden weapons and combines their power creating a Mega Weapon. The Mega Weapon then gave Garmadon the power to grant him any whish but drains his power every time he uses it. In the episode "Wrong Place, Wrong Time", Lord Garmadon uses the Mega Weapon to go back in time and make it so that Lloyd would never become the green ninja. The ninja later find out about his plan and jump into the portal Garmadon created with his Mega Weapon to stop him.
Gallery of Variants
- 2111 Kai (Standard variant)
- 2505 Garmadon's Dark Fortress (Standard variant)
- 2507 Fire Temple (DX variant)
- 2508 Blacksmith Shop (Standard variant)
- 2518 Nuckal's ATV (DX variant)
- 2254 Mountain Shrine (DX variant)
- 2258 Ninja Ambush (Standard variant)
- 3856 Ninjago (Microfigure)
- 30083 Dragon Fight (Standard variant)
- 9558 Training Set (Kendo variant)
- 9441 Kai’s Blade Cycle (ZX variant)
- 9443 Rattle Copter (ZX variant)
- 9449 Ultra Sonic Raider (ZX variant)
- 9456 Snake Battle (Kendo variant)
- 9561 Kai ZX (ZX variant)
- 9591 Weapon Pack (NRG variant)
- LEGO Battles: Ninjago
- LEGO Battles Ninjago:Collector edition (with Kai minifigure)
- LEGO Ninjago: Nindroids
- TV Series
- Ninjago: Masters of Spinjitzu
- Pilot Episodes
- Season 1
- Season 2
- Season 3
- LEGO Club Magazine Issue 1 2011 - Front cover, contents, Lessons of the Dojo!, Spinning to Win!
- Kai may be based on the Red Ninja from the Ninja sub-theme.
- In LEGO Battles: Ninjago, Kai doesn't wear his hairpiece from the show and his 2014 variant, instead he uses Nightwing's 2006 hairpiece in brown.