Asorah's Dreaded Gateway Key is the second Gateway Key, which requires the player to defeat Asorah, The Fallen, and obtain a Dreadlands Infused Powerstone in order to craft. It can only be used within The Abyssal Wasteland and The Dreadlands, but also works in Omothol (if you happen to still have one at this point).
Materials used to craft Asorah's Dreaded Gateway Key is:
If you right-click on the ground while holding this tool, it will form a portal. This will however not work if the path is too narrow, in which case nothing will happen (which would indicate that it was used at a incorrect location). If you happen to use it in a dimension that isn't the Abyssal Wasteland, the Dreadlands or Omothol, it will also prompt a message pointing out that it isn't working.