Umbra

The Umbra are an intelligent, nonhumanoid alien species of the galaxy that is intensely hostile to other forms of life and have represented a threat to the Imperium of Man on numerous occasions. Very little is currently understood about this hostile and enigmatic species of xenos. An Umbra appears to be a black sphere to the naked eye, but it possesses the capacity to manipulate shadows as weapons. The Umbra were known to be related in some way to the Warp and were often sighted near starships’ Warp-Drives. With an ability to manipulate the shadows, the Umbra display a direct aversion to light. Experiments performed by Magos Biologis Sharle Darvus demonstrated that containment within an area lacking any shadows was sufficient to euthanise the creatures.