Metalkind

The Metalkind are a sapient species of boron-based lifeforms. They are one of the two races native to a binary planetary system at the eye of the Tornado Nebula, the other being the Fleshkind.

Biology
Metalkind are metallic-looking humanoids. Despite their robotic appearance, they are a naturally evolved species from a planet in which all life is based on boron, as opposed to carbon. Their metalloid structure makes them heavier than most other humanoids.

Culture and society
The Fleshkind and the Metalkind have been at war for centuries. Metalkind technology includes means to render themselves invisible.

Appearances

 * The Sarah Jane Adventures, series 5, "Sky" (2011)