In season 3 episode 9 kurogiri was knocked unconscious yet noumus started to appear from a black warping liquid. What's the black warping liquid and who controls it?
That black warping liquid is a Quirk called Transmission!
From the wiki:
Transmission is a stolen Quirk from an unknown person used by All For One
This Quirk can produce a black liquid that acts as a portal, similar in nature to Kurogiri's Warp Gate. Also similar to Warp Gate, this black liquid can also teleport people by engulfing them whole.