Venat not doing anything is a giant plothole. Just tell them... they would believe it. Then get all the gang together, build an Imperium-like spaceship (Ancients should've been able to pull it off), follow the GPS tracker from Venat and Exterminatus the hell out of Ultima Thule before Meteion had the time to prepare.

Also, you really want to tell me that a giant memory wiping device didn't record what and whom it operated on?

But I get it. We anime. So emotion, much tears. I just hope further stories will be a bit more logical, because this stuff falls apart the moment you activate your brain.