Oh well that's an interesting different thing that I didn't entirely expect! I like the start of it all.

I'm really curious on a few aspects...
- How individual Astartes are referred to among The Cornucopiad (Cornucopiad Marines? Corn Marines?)
- How they got into the dual times of Assassination and Civilian Evac. The latter makes sense with where they're from, but maybe you moreso mean "Strategic Strikes" than Assassination since Astartes probably want to kill staffs, not generals.
- How the Mechanicum feels about [i]The Coming Rain[/i] - unless it's more a modification to a smaller warship to create a full Strike Cruiser using the components of the colony ship, which more makes sense I think.