So as of Scourge wrapping up, the Void was ultimately defeated by Nova's cosmic reinforcement gang (which included Gladiator and Beta Ray Bill) briefly holding him in place in order for Merged Silver Sentry to super speed ram himself into the Void, which due to Surfer's current state triggered a re-merging of the Void back into the Sentry and back to the black haired, red costumed look.
Then to add to the space tearing shenanigans the Void was up to, it was revealed the reason the Cancerverse was able to escape its previous subspace quarantine was because the effort of Sentry unmerging himself generated an explosion powerful enough to ripple through both the Negative Zone and the Cancerverse.
What Merged Sentry did back as himself was heat vision one-shooting a Nova who has absorbed the entirety of the Cancerverse legions into himself (which required the cosmic gang, also including Surfer now, to pool their power to allow the merging to complete without Nova's body overloadsploding in the process). This caused the evil sentient Cancerverse breach Sentry opened to close back in, I assume because it couldn't keep its footing in the Negative Zone with no one left to spread infection.
Then Sentry decided to stay behind in the Zone to well keep sentry.