In The Wheel of Time
, Dark One is the antithesis of Creator
, embodiment of chaos
, destroyer of order
He is also known as Shai'tan, Leafblighter, Sightblinder, Old Grim for a few.
The origins of Dark One are unclear. Some say he was created by Creator, others that he came from nowhere, others that he is chaos that just... is. Others say he might even be mortal, and yet others say Padan Fain may become the next Dark One.
This way or that, the battle against him in the form or the other has lasted, as far as we know, for the age of the Wheel of Time, and will last, they say.
Dark One is constantly trying to break free of his prison, to fight the Tarmon Gai'don against The Dragon, and (apparentlty) gets locked up again and again.
He speaks in similar fashion to Terry Pratchett's Grim Reaper; in capitals.