Grey Alien Megastructures - ACK's Barbarian Conquerors of Kanahu & Colonial Troopers Knight Hawks rpg

 Yesterday afternoon, I took a bit of time to refine some campaign ideas when it comes to our ACK's Barbarian Conquerors of Kanahu & Colonial Troopers Knight Hawks rpg affair which has been taking on a life of its own. But a question came up last night post Thanksgiving meal in our local coffee shop, 'How are the Greys moving their interstellar assets  from one place to another.'  This is going to pick up right from where we left off here. 

 

So the Greys are some of the most dangerous interstellar powers around. The Greys move military & exploration assets into other intergalactic star systems & outer galaxy points. They use interstellar megastructure known as stellar engines. Specifically the Grays use the Shkadov thruster set up because the Greys are  a Type-II civilization on the Kardashev scale. The Shkadov thruster set up enables the Greys to take full advantage for the star systems that they settle in. But why?! Because let's look at the Wiki entry on the system set up; "One of the simplest examples of a stellar engine is the Shkadov thruster (named after Dr. Leonid Shkadov who first proposed it), or a Class A stellar engine.^[4] Such an engine is a stellar propulsion system, consisting of an enormous mirror/light sail—actually a massive type of solar statite large enough to classify as a megastructure—which would balance gravitational attraction towards and radiation pressure away from the star. Since the radiation pressure of the star would now be asymmetrical, i.e. more radiation is being emitted in one direction as compared to another, the 'excess' radiation pressure acts as net thrust, accelerating the star in the direction of the hovering statite. Such thrust and acceleration would be very slight, but such a system could be stable for millennia. Any planetary system attached to the star would be 'dragged' along by its parent star. For a star such as the Sun, with luminosity 3.85 × 10²⁶ W and mass 1.99 × 10³⁰ kg, the total thrust produced by reflecting half of the solar output would be 1.28 × 10¹⁸ N. After a period of one million years this would yield an imparted speed of 20 m/s, with a displacement from the original position of 0.03 light-years. After one billion years, the speed would be 20 km/s and the displacement 34,000 light-years, a little over a third of the estimated width of the Milky Way galaxy." 

A digitally colorized pen & ink drawing of two grey alien By MjolnirPants

The Greys move their star systems where they want & before you know it they will be on your PC's doorsteps. The Greys came up into their own right at the point when the Elves were worshipping Chaos. The Chaos gods ascended into several worlds where the Greys had established colonial holdings causing conflict. The Khepri took full advantage of this conflict to establish themselves. The Khepri are the interstellar equivalent of cockroaches. They take advantage of races by making beach heads in many worlds. 'The Secrets of the Nethercity' have a killer example of these Khepri outpost. Are the Khepri a precursor race?! We shall see. 

And its within this point that the Greys became a bit corrupted by Chaos & began to cross breed their own humanoid Chaos based troops. But these are seldom used because of the swath of destruction that they cause. The Greys have a number of Dyson spheres that they use to sometimes for stellar engineering & the occasional star system cleansing. 
But it is only recently that the Greys have began to build  Caplan thrusters; "Astronomer Matthew E. Caplan of Illinois State University has proposed a type of stellar engine that uses concentrated stellar energy (repurposing the mirror statites from Class A) to excite certain regions of the outer surface of the star and create beams of solar wind for collection by a multi-Bussard ramjet assembly. The ramjets would produce directed plasma to stabilize its orbit, and jets of oxygen-14 to push the star. Using rudimentary calculations that assume maximum efficiency, Caplan estimates the Bussard engine would use 10¹² kg of solar material per second to produce a maximum acceleration of 10⁻⁹ m/s², yielding a velocity of 200 km/s after 5 million years, and a distance of 10 parsecs over 1 million years. While theoretically the Bussard engine would work for 100 million years given the mass loss rate of the Sun, Caplan deems 10 million years to be sufficient for a stellar collision avoidance.^[5] His proposal was commissioned by the German educational YouTube channel Kurzgesagt" 
Much of this technology came from a technological exchange with the 'Cloud Giants' and has been stolen by the Skinnies. But the Greys are working on several  secret project and its here that the PC's have very recently began to inquire. 

The alien necromancers of Narri have been at war with the Grey over several star systems causing the Greys to field plasmas based weapons. We've been looking into using  Alternative Armies Ion Age miniatures to simulate one or more of the races we're playing with.  And the bat just got moved up.