Bricktron

Bricktrons are little yellow creature that inhabit the world of Castle Story.
Three professions have been confirmed which the Bricktrons can do: Builder, Miner, and Lumberjack.

We know that Bricktrons come from rocks, however we don't know their full capabilities.

It is speculated that the Bricktrons may also play a major role in defending your castle.
This could be why we have seen what looks like Bricktron Archers and Bricktron Knights.
However, this is all speculation based on the images available to us at this moment.