Actually, I was hoping the Supremes might have helped with mark two of project severance

(Just realised only half of my last post went through too. Basically, what I said was

2nd was defences. They were able to fend off the Reapers for long enough to complete their weapon
The weapon worked by detecting a specific U particles, an occurrence from the border dimension between universes which vary in shape and size depending on the pressure, which forms from different universes, thus making it a sort of point of origin thing
With it they were able to kick the reapers out of the universe 
It strengthened the universe borders, preventing the reapers coming back again
They might have had Supremes help with this, because I don't think the Supremes would sit around on their arse for 10000+ years while the Collective tries to build a device to end the Universal War
This gives us a reason to not have the Reapers curb stomping us the second we show signs of becoming space age again as well.