The Guards where part of the "Hub" defence system.
Taken over long ago by "The Narrator" these machine make themselves part of the walls of the middle room to blend with the environment.
Called upon, they form back into their humanoid forme to eliminate the threat.

They are equipped with extremely long and sharp arm blade to cut trough anything, including armor and hard material like stone. They also have a beam arm canon the which they use when the melee option is not usable. Its able to melt trough pretty much everything the beam touches.

It is said they where once a organic organisme of which was transmuted into one of these, a mind of a soldier inside a deadly killer robot...