The Shrouded One is a strange being with very little known about him/her, except that they are exceptionally beautiful. They are so beautiful in fact, that nobody can look upon their face without going mad, hence the reason they wear a shroud at all times. They first appeared in the creepypasta "The Shrouded One".
A quote from the original story
“'We looked upon the Shroud's face, and felt inexplicable pain, something beyond all description. The sensation of our hearts being torn apart, nerve by nerve, breaking into millions of glass pieces. The feeling of every vein in our bodies singing, soaring being bliss and overwhelming us with so much awareness of ourselves that we ached. A burning, piercing, thrilling ache.'” — An unnamed victim