Using this Quirk, Kurogiri can create and manipulate a dark fog that acts as a portal. When the user produces a mass of the dark fog, it transports anything it comes in contact with to a nearby location. Kurogiri can even shroud himself with the black mist to hide his true body and personally transport anything out of himself.
The portals that he creates are based on coordinates and thus to open them means he must be able to pinpoint the exact position where he wishes for each portal to open up into.
Its only main weakness is that a part of his real body must be present at all times, allowing foes the opportunity to hit or immobilize said part. It is said that this ability is a very rare type of Quirk. The only other weakness is that since it is a Quirk that opens portals based on coordinates, he cannot search for missing comrades if he does not know their exact position.