Kai is the ninja of Fire, and though he is a hero now, he came from humble beginnings.
His father was a trusted ally of Sensei Wu and the two adventured together for many years.
Wu would later hide the map showing the locations of the Four Weapons of Spinjitzu in his friend’s blacksmith shop.
Kai was the last member recruited for the team by Sensei Wu and the last to achieve his full potential (which happened when he saved Lloyd from the belly of an active volcano!)
He can be hot-headed and impatient, but is trying to control that.

• For the first two months of his life his parents called him Ash.
• Kai once by accident forged a weapon called a 'Swingana' … Part yo-yo part sword. It was not a big success.
• When Kai uses his elemental power in a vehicle, it gets powered up and engulfed in flames … which is why flying a hang glider is a bad idea.
• Once Kai singed off his eyebrows with the sword of fire. But no one noticed because he painted them back on with a black marker.
• When Kai's sister Nya was a baby, he used to juggle hammers to entertain her. When he dropped one on his foot she laughed the hardest.