Nya (pronounced "Nee-uh") is one of to female characters from the Ninjago theme, though she is the only one to appear in a set. She is the younger sister of the fire ninja, Kai. She and her brother worked at a blacksmith shop called Four Weapons, where she is shown to be a more patient blacksmith than Kai. Nya seems to have a secret crush on the lightning ninja, Jay. Though she is not trained as a full ninja, she has much natural ability. Nya is courageous, just like her brother, and is gifted with psychic powers. Nya takes the identity of Samurai X in Rise of the Snakes. It is revealed that she is Samurai X in, The Snake King.
In Ninjago: Masters of Spinjitzu, Nya and Kai are working in their family blacksmith shop, Four Weapons. When they are approached by Sensei Wu who shows disdain for the weapons they make, saying they are useless in the art of stealth. He also says there is only stuff for a samurai, but not stuff for a ninja. Kai drives him off, who in turn disappears when Kai turns his back. Moments later, a dark cloud appears over the village, with local farmers being the first to notice. On the edge of the hill, a large vehicle (the Skull Truck) appears along with many motorcycles, all with skulkins on board, notably Nuckal, Kruncha, and Samukai. The farmers attack the skulkins, only to run at the last second. Then, Kai, wearing hand-crafted samurai armour, engages in battle, with Nya joining in. Kai is nearly killed by Samukai, only to be saved by Sensei Wu, who reappears just in time. He is not able to save Nya, as she is kidnapped under the orders of someone called "Lord Garmadon."
Later, while Sensei Wu and the four ninjas, Kai, Jay, Cole, and Zane are sleeping in the Forest of Tranquility, location of the Sword of Fire, Kai is woken by Nya. She runs away, and Kai chases her through the forest, eventually entering the fire temple. Nya is then revealed to be an illusion made by Lord Garmadon in a shadow form. He exploits the fact that Kai had forgotten his sword, and that the real Nya is hanging from chains above the lava in the temple. Garmadon tells him the only way to save Nya is to pull the Sword of Fire out of its rock. Kai obtains the sword, cuts Nya free and is then confronted by shadows controlled by Garmadon. Sensei Wu arrives to save them, and jumps on a rock that is going down a lava fall so he may go to the Underworld. Nya then returned to her village where she waited for Kai and the other ninjas to return.
In the Spinjitzu Smash online game, Nya appears in Jay's campaign. She accompanies Jay while he builds his balloon and travels to the Sky Temple. Also in the LEGO Battles: Ninjago game, Nya is shown wearing the minifigure's nurse outfit; this concludes that Nya is a nurse and her ability is healing.
Nya's hair-piece is the same as that first used for Irina Spalko from the Indiana Jones theme and Dyna-Mite from the Agents 2.0 theme. Nya and Lloyd Garmadon are currently the only minifigures from the Ninjago theme to have a double-sided head. On one side, she wears a red veil. On the reverse side, her whole face is visible, revealing a neutral or angry expression. She has been depicted wearing a sleeveless, red dress which is decorated with a phoenix pattern and a red jumpsuit.