Shadow Kids are the same height as the other regular children encountered in the Maw, including Six and the Runaway Kid. Their bodies however seem to be made of a dark smoky aura, almost as if they are living shadows. Their only distinct features are the white masks they wear on their faces and the shadowy shackles on their right legs.
When the Runaway Kid takes out a second figurine to open the passage, the Lady suddenly disappears, and the light in the entire library turns off. It is at this moment that the Shadow Kids appear (the player can be guided by the laughter of children). They will start attacking the Runaway Kid by flying towards him at breakneck speed and kill him.
To fight them off, the player must use a flashlight, from the light of which they burn out and dissolve in the air. Shadow Kids will attempt to evade the light by walking sideways, forcing the player to follow their movement with the flashlight. Multiple Shadow Kids can spawn at the same time, testing the player's multitasking skills. Once a Shadow Kid's body has been completely vaporized by light, its mask will fall to the ground and shatter.
Often, players can hear the whisper of the Shadow Kids. If they listen, the following words can be heard:
- You're... A... Goner
- Hello there
- Do you hear her singing?
- Her intentions were to follow.
- Of course they were
- Yes she does.
- But that can't be right
- The light
- About the time it was talking
- It is looking with its sight
- Until Six...
- The laughter of the Shadow Kids are sound special effects, that are often used in other projects.
- The Shadow Kids' masks are similar to the faces of the dolls that the Lady is tending to in her library.
- The Shadow Kids are one of the few characters in the Little Nightmares games that speak. They can be heard whispering pure English to each other.
- When asked about the Shadow Kids, Tarsier Studios writer Dave Mervik stated "They’re nobody in particular. Just like all children, they’re forever being left behind; and just like all shadows, they’re difficult to escape."
- Shadow Kids are one of the few antagonists in the franchise who take the form of children, along with the Pretender and the Bullies.