What I had in mind originally was to introduce the 'Beyond Solar' Order, which the 'Mysterious robed man' is the leader of. Due to the Empire being militaristic in nature any diplomatic relation would be incredibly militarized and maybe too hostile for some to enjoy. I most certainly imagined something with the swarm, I like the idea of having some type of constant military threat, that will make the northwestern flank into the more bloody front, which translates to better soldiers, etc. What I was thinking of from your INCREDIBLY good introduction, Terminal (thank you for that one.), that I might push the northwestern front and introduce the Beyond Solar Order, which is as a mystical, 'supernatural' order which act's beyond the Empire. Basically a secret order.