Abyssilisk

Greater Zaghast, Abyssilisk - Greater Zaghast are the most evolved, largest and deadliest of the Zaghast. The Abyssilisk is large, has a ranged spitting attack and two massive scythe arms and a blade like snake tail. Both a menace in ranged and melee combat the Abyssilisk is not to be taken lightly.
Humanity has colonized the depths of Mars in order to harvest minerals, expand their presence on Mars and ship much needed resources back to earth. Humanity has managed to terraform Mars, making it habitable without needing special suits to traverse Mars' atmosphere. As a result Mars transforms from a harsh cold climate to a humid greenhouse climate. This stirs up and ancient alien/mutant race which in turn becomes very active, seeking to kill and infect/mutate millions of colonists. The colonies stand up a paramilitary force known as Ranger command. The Rangers constantly take the fight to the Zagahst, keeping the colonists safe and keeping Mars from being overrun.