The Crimson King, the big bad of the Dark Tower cycle. When Roland finally meets him he is an insane old man trapped on a balcony outside the tower with a crate of sneetches (an homage to JK Rowling's Harry Potter series)
"Roland saw exactly what he had imagined: an old man with an enormous nose, hooked and waxy; red lips that bloomed in the snow of a luxuriant beard; snowy hair that spilled down the Crimson King’s back almost all the way to his scrawny bottom. His pink-flushed face peered toward the pilgrims. The King wore a robe of brilliant red, dotted here and about with lightning strokes and cabalistic symbols. To Susannah, Eddie, and Jake, he would have looked like Father Christmas. To Roland he looked like what he was: Hell, incarnate."
His robe is covered with various symbols from the books, including the sigul of eld, the eye of the crimson king and the hourglass shape found on Mordred's spider form. There are 19 of them in total :)