How about something like a Death Star or an Unknow Planet Size Ship For a legion to take down and #&$# and a random event
Or some sort of thing that will be a threat to all players like as long as this Tyranite Matter Absorbing Black Hole is alive Planets produce like 20% less minerals or reserach or w/e XD
or a bunch of parts can be looted from these giant things XD Maybe A NOC thata fter been scanned like 3000 times and using 40000 reserch points on it you find a way to destroy it and thats when battling can start

kinda what they have on Castle Age(I said KINDA!!)