After the First Spinjitzu Master created Ninjago, humans populated the island. It is unknown if he created them or if they originated from elsewhere. Early in the world's history, he chose several humans to give Elemental Powers, making them Elemental Masters.
At some point, humans and the Serpentine lived in fragile harmony, thanks to the First Spinjitzu Master and the leader of the Serpentine tribe that would eventually be known as the Pyro Vipers, whose name was Mambo V. This peace existed for millennia but was threatened when the First Spinjitzu Master's children trespassed into the Serpentine territory and set off a chain of events that led to the young sorceress Aspheera usurping King Mambo and nearly declaring war on humanity. Wu and Garmadon defeated her using Forbidden Spinjitzu, restoring Mambo to power, thus maintaining the peace.
A thousand years later, a war between humans and Serpentine began because of mistrust between the two species. Eventually, they almost agreed upon a peace treaty. Before that could happen, Chen deceived both sides, telling them that the other side is going to betray them. The Elemental Masters managed to defeat the Serpentine thanks to the Sacred Flutes and the Serpentine were locked in tombs, the Anacondrai generals were sent to the Cursed Realm, and Chen and Clouse were exiled to an island for 40 years.
40 years later in modern times, Chen returned, now with an army of Anacondrai warriors. With the help of the Serpentine and the ninja, Garmadon, sacrificed himself to send them to the Cursed Realm. This was done to release the original Anacondrai. Morro, a former student of Master Wu escaped the Cursed Realm at this time, planning his revenge, which was to bring The Preeminent into Ninjago.
In the Cloud Kingdom
In the Cloud Kingdom, monks are responsible for writing the destiny for people.
In the Never-Realm
- Garmadon (of Oni and Dragon descent)
- Lloyd Garmadon (of Oni and Dragon descent)
- Wu (of Oni and Dragon descent)
Holidays celebrated by humans
Unlike humans in real life, they do not have visible noses or ears. However, in "Can of Worms" Jay asks if Wu could teach them to "find out if a man is lying by the twitch of his nose", and in "The Royal Blacksmiths," Lou says "If my ears weren't attached to my head, they'd be running away!"
Females have visible eyelashes and lips while males do not, though female children do not have visible lips. Females also have highlighted hips, but since Season 5 this is no longer true and it only manifests itself on released Minifigures or in some exceptions.
Some people, specifically big-figs as Dogshank and Killow, have more realistic hands instead of classic LEGO hands, so they have five fingers. Other instances of more realistics hands include a mummy hand in the relic room in "The Explorers Club" and an icon of a closed fist is seen on a wall at Benny's Arcade Emporium in "Level Thirteen".
- The Skulkin with abnormal head shapes may have been an early evolution of human when they were alive.
- NPCs most likely became humans rather than androids when they traveled to the real world, with their code being turned into genetic material, the opposite of how the ninja were able to enter Prime Empire by becoming code.
- In the TV series, humans do not operate the same way as LEGO Minifigures do in real life, meaning their body parts do not individually separate from each other. However, androids operate this way, as do humans in various media outside the TV series:
- According to Tommy Andreasen, it is possible that the First Spinjitzu Master could not create life on his own and therefore brought people from other realms.
- In "Boobytraps and How to Survive Them", Clutch Powers says, "Nein danke," which means "No thanks" in German. This may indicate that there are different languages and cultures in Ninjago, such as the Egyptian culture of the Pyro Vipers and the English culture of the Explorers Club. Gravis' turban may also suggest the existence of religion within Ninjago.