The Hidden is a cryptic individual, who would rather observe and strike from the shadows. This has given her an aversion to sunlight. Not only does she serve The Tall One, she is also wanted by several servants of the Ouija Man to join their cause.
It is wise not to trifle with The Hidden, for the Slender Man sees her as his actual daughter, granting her immense protection and power. She discovered this after asking him directly, his response providing enough information to know that The Hidden could easily be one of the most influentual Proxies to date, that information not self imposed. The Hidden is well aware of her status and often lives up to it, occasionally speaking down to fellow servants.
The Hidden is also known as "The Black and White Princess", signalling to her family ties to the Tall One.