Curate, connect, and discover
okay, to summarize where my theory is at regarding Kurogiri’s mess of quirks:
1. his original quirk was sent into overdrive by massive amounts of Trigger, which is (at the very least partially) the reason why his body changed permanently. his quirk is just covering all of him now. he is his quirk, because that’s all that AfO needed from him. and that’s why it has similar properties to a mutant quirk in regards to the lack of effect from Erasure - it can cancel out his portals, but it doesn’t change his body 2. he seems to have lost the ability to make completely solid clouds, or clouds at all, but the way he builds his portals is based on that 3. his head and neck where the brace sits is the body part he can actively emit the mist and portals from. it’s the only part that needs to be physically present to do so, and the brace serves to protect this one vulnerable spot (basically his Achilles Heel) 4. when in full fight mode, where only the brace seems to be tangible, he might be using a warp portal directly at the base of his neck to keep the rest of his body in a safe place while he fights. this should also allow him for better mobility since he can freely move the portal around to wherever he needs his head to be