As the title says.
I had them spawn early into game on a gigantic map with five other races. I'm in the North, and I have an emergent Yor empire to the East currently. South and South-West I have the Terran and Alterian respectively. Both their fleets and infrastructure were wrecked and I thought I could get away with building and teching up my military so that I could fend them off and also capitalise on the situation. That was until fleets of large Dread Lord ships began making their way up to my empire and a battle of attrition ensued, where I was slowly able to push them back at great cost.
The Dread Lords have not taken any planets as far as I can tell and my fleets are much better at countering, but now I have to take a chunk out of the Yor as they have been building up. It's also been one of those matches where all the mega events are happening, despite being set to rare.