Dr. Calis was the chief scientist in charge of the X-13 research facility under the command of Dr. 0 in the Big Mountain Research and Development Center. Much to the annoyance of his subordinates, Calis had a tendency to become furious over the littlest things and had a no nonsense work ethic in the lab.
He asked Captain Hamm, Big Mountain's security chief, to provide a shipment of cattle prods in order to control the nightstalkers, who were becoming increasingly aggressive. Eventually, he evidently decided to face the nightstalkers directly, an error in judgement that cost him his life. His skeleton, still clad in a lab uniform, can be found sprawled on the ground outside the nightstalkers den. It is also possible that this event allowed the nightstalkers to escape into the wild, leading to the further death of most of the scientists in Big MT with the escape of cazadores.
- Due to a requirement of the game engine, his limbs will still bleed like most normal corpses if severed by the player. If the body is moved around and if you look closely, you can see his head isn't actually connected to his body (there is no spine), but it still acts as though it's connected.
- When using the Atomic-valence tri-radii-oscillator Calis looks almost like a ghoul.