Inktale is an AU where only Sans exists (although Papyrus or Ink!Papyrus may be there as well, but he is unseen so far). His name is Ink!Sans (but people often just call him Ink). He is the protector of imagination and alternate universes. He often fights Error!Sans, since they always argue, and that likely prevents destruction of timelines. Ink!Sans is a protector of AUs (although some view him as or mistake him for a creator of AUs) while Error!Sans is a destroyer of AUS. Comyet, a user on Tumblr, was the one who created Inktale; Errortale's creator is loverofpiggies, also a Tumblr user.
About the AU
Ink!Sans (collectively known as Ink) lives off the creativity of artists and lives outside the timeline. He supports artists to create new AUs and keeps adding art to the fandom as long as he can. If creativity runs low, Ink loses energy and falls ill. His goal is to fight art blocks (actual entities), and he can use his massive paint brush to create and bring life to anything he wishes, except the already dead. He can also teleport to any AU from any kind of liquid mixed with paint.