Karkat has grey skin Source: Every page with Karkat
-Mod L
Aradia has spoken with Doc Scratch before, seemingly consulting him for information to Bec Noir’s appearance in their session, or for information concerning the Scratch.
Therefore, Doc Scratch has spoken to Vriska, Kanaya, Karkat (briefly), Gamzee, and Aradia as far as the trolls are concerned (Barring Terezi who contacted him).
==> Submitted by 777crimsonchaos