These monsters make their appearance in Legend of the Banishers Chapter 2: Enter the unknown. We first see them as Michel Ryo is currently on his way to start his intiation duel he find his friend Cole Viceman duelling against an AI computre using these strange monsters. These monsters are all Dark Rock monsters
The main focus of this archtype is there defence points. All of them can activate their effects through reducing their defence by a certain amount, but can also gain a certain amount back by discarding Rock type monsters. These also come with secondary effects which require a tribute in order to activate them. The star card for the arctype is Bouldark Giant. This brute comes with some major effects one increasing its own attack and the other to help swarm the field, in short it is a major support for the archtype.
All the monsters within the archtype have the image of a shadowy aura surrounded by a mass of rocks. The aura represents their attack and the rocks their defences. Any changes to their stats affect the mass of rocks surrounding them and the size of the aura. One monster which changes differently is the Bouldark Totem, its effect grants it an extra level so as it is based on a totem pole, when its effect is activated it gains another section on top. This is the only major difference, apart from that they all contain the same dark aura and rock mass.