An Imp is a species of Xeno alien caretaker that can launch fire and plasma balls, from cannons integrated in their arms. They are very wide and tall and can easily kill a NOVA trooper. They appear only in N.O.V.A. 1.
Their armor is built specially for there ability to launch plasma and fire from their arms. Like most Xenos they have energy shilds. There are stronger versions with more powerful energy shields as well. Don't be fooled the red ones aren't something to underestimate either.
Imps were a savage sentinent aliens that the Judgers chose to be their amongst their Xeno caretakers when they entered hibernation. They were biotically enhanced and receved specially made armor for their pyrokinetic ablilities. They were sent to destroy humanity but were stopped when the Automated Command Core that initiated the endeavour was damaged by Kal Wardin and stopped by the Judgers.