Kai

1 Biography
 * 1.1 Kai's Early Life
 * 1.2 Way of the Ninja
 * 1.3 The Golden Weapon
 * 1.4 King of Shadows
 * 1.5 Weapons of Destiny
 * 1.6 Flight of the Dragon Ninja
 * 1.7 The New Masters of Spinjitzu
 * 1.8 Return to the Fire Temple
 * 1.9 Rise of the Snakes
 * 1.10 Home
 * 1.11 Snakebit
 * 1.12 Never Trust a Snake
 * 1.13 Can of Worms
 * 1.14 The Snake King
 * 1.15 Tick Tock
 * 1.16 Once Bitten, Twice Shy
 * 1.17 The Royal Blacksmiths
 * 1.18 The Green Ninja
 * 1.19 All of Nothing
 * 1.20 The Rise of the Great Devourer
 * 1.21 The Day of the Great Devourer
 * 1.22 Darkness Shall Rise
 * 1.23 Pirates Vs. Ninja
 * 1.24 Double Trouble
 * 1.25 Ninjaball Run (Episode)
 * 1.26 Child's Play
 * 2 Appearance
 * 3 Personality
 * 4 Weapons
 * 5 Trivia
 * 6 Gallery

"A ninja never admits defeat." - Kai

Kai is the Red Ninja of fire. His younger sister is Nya, who is also the mysterious Sameri X. He was chosen to protect the Green Ninja (Lloyd) along with the other three Ninja. Kai was the last Ninja to be chosen by Sensei Wu. He is the only Ninja known to have a sibling and he was the final Ninja to unlock his True Potential.

Kai's Early Life
Kai, along with his sister, were the children of the blacksmith and owner of Four Weapons. When their father died, Kai took it upon himself to keep the family business going and swore he would become an even better blacksmith than his father.

Way of the Ninja
When the Four Weapons Blacksmith shop was attacked by Samukai and his Skeleton army, Kai attempted to defend it with some samurai armor he made. The armor was slow and clunky however, and he was soon subdued and would have died if it wasn't for the quick action of Sensei Wu, even though Nya was kidnapped in the process. Sensei Wu then told Kai about The First Master of Spinjitzu and his two sons who fought over the four Golden Weapons, explaining that an honest man had been entrusted with the map to their resting places and the honest man was Kai's father. Sensei Wu took Kai to the Monastery in order to train him to be a Spinjitzu master so he could save his sister, and all of Ninjago. During his training, Kai had to learn patience and how to harness the "fire" inside of him. This training consisted of running a course before Sensei Wu finished his tea. Kai accomplished this after several days by knocking the teacup out of Sensei's hands when he was about halfway through the course with his wooden training sword. He then told Kai to get some rest, and that his final test would come in the morning. 

The Golden WeaponEdit
Later that night, while Kai was pondering Sensei Wu's training and brushing his teeth, he was set upon by three black-suited ninja. Kai was able to fend them off for a while, disorienting them on the training course. Before they could fight much longer, however, Sensei Wu arrived and told them all to stop, at which the three ninja revealed themselves as more of Wu's students. Wu used Creation to give each of the Ninja a suit that matched their elemental properties, and introduced them to each other. He then told them what they needed to do to defeat Lord Garmadon, who is Sensei Wu's brother. Cole interjected and asked if they were still to learn Spinjitzu first. Sensei Wu then informed them that they each already knew it, but it must be unlocked at the right time. Then Sensei Wu said that they would take the horse carriage (pulled by Kai and his fellow Ninja) to the Caves of Despair, the location of the first Golden Weapon, The Scythe of Quakes. At the Caves of Despair, Kai ran ahead of the other Ninja while Cole was formulating a plan. The other three Ninja chased after him, and caught up to him just before the chamber where the Scythe was housed. Jay then accidentally revealed their position to the skeleton army digging for the weapon, and they were soon in a battle. After Jay discovered the key to unlocking his Spinjitzu, Kai and the others were quick to follow. They used it to drive off the skeleton army, after which they discovered that they had a bigger problem in the form of the weapon's guardian, the Earth Dragon. Kai happened to be holding the Scythe at the time, and decided that the only way out was to use it, contrary to Sensei Wu's instructions. After escaping, Kai was strictly repremanded by Sensei Wu, and they went onward toward the next weapon, The Shurikens of Ice.

King of ShadowsEdit
While on their way to the Frozen Wasteland, the location of the Shurikens, Wu told the Ninja about the most powerful technique in Spinjitzu, the Tornado of Creation. Kai began to attempt it, but was stopped by Sensei Wu, who explained that it could have disastrous consequences if done incorrectly. When the Ninja arrived at the location, they discovered several skeleton warriors frozen in ice, and deduced that they had been the second group to arrive there. When they discovered the Shurikens suspended from the ceiling, they lifted Zane up to grab them. When he did he was frozen over with ice, and the Ice Dragon awoke. The Ninja then used Zane as a sled to escape, and went to the hiding place of the Nunchucks of Lightning, the Floating Ruins. On top of the chain, Jay found the Nunchucks, as well as the Lightning Dragon. As they were being chased by skeletons, the Ninja used Jay's wing-glider invention to leap off the chain and get away to the Forest of Tranquility. While they were sleeping that night, Kai thought he saw his sister Nya. He got up and chased her to the Fire Temple, where he discovered that it wasn't really Nya, but a shadow deception created by Lord Garmadon. His sister was in the Fire Temple however, only suspended over a pit of lava. Kai had to remove the Sword of Fire from its pedestal to cut the chain and save his sister, which was Garmadon's plan all along. He controlled Kai's shadow, and used it to defeat him. The shadow couldn't be hurt by Kai, but Kai could be hurt by the shadow. Garmadon made multiple copies of the shadow, which made quick work of Kai, and obtained the Sword. All would have been lost if Sensei Wu hadn't intervened at that moment, using his own shadow to defeat Garmadon's Shadow Warriors, regaining the Sword. Garmadon then decided to awaken the Fire Dragon, knowing the guardian would impede the band. The Dragon blocked the entrance to the temple, which meant it would be easy for Garmadon to bring the other three weapons to the temple and unite them there, as Samukai had ambushed the other Ninja. Sensei Wu then sacrificed himself to go to the Underworld in order to keep the weapons apart.

Weapons of DestinyEdit
Kai and Nya discovered that the Dragon only wanted to protect the Sword, and the Ninja used the guardians to go to the Underworld to help Sensei Wu. The Dragons performed their variation of Spinjitzu and crossed over, landing not far away from the Skulkin Fortress. They tried to make their way overhead by hopping across stalactites only to grab onto the legs of Spykor by mistake. Out of fear they dropped down to the floor below, where they were noticed by Nuckal. They were going to defeat the Skulkin until the Spykor descended to the ground, surrounding them. Thinking fast, Jay remembered the Tornado of Creation. Although Zane protested about disastrous consequences, they used the Tornado, successfully defeating their enemies. They arrived in the fortress to witness Sensei Wu being defeated by Samukai. Samukai acquired all of the Golden Weapons and planned on betraying Lord Garmadon, but Garmadon anticipated this and told him he could not handle the power of the weapons. After the massive power of the weapons destroyed Samukai's body and transformed him into a portal, Lord Garmadon escaped. Sensei Wu assured him about Garmadon and the Ninja departed the Underworld. Kai and his new friends went back to the Blacksmith shop and were greeted by Nya and several villagers.