Proxies are the servants of the Slender Man, commonly seen wearing hoodies and masks in order to hide their identities. Many proxies suffer from mental illnesses, such as multiple personality disorder, bi-polar disorder, schizophrenia and a few others.
Proxies possess two abilities by default, granted to them by The Slender Man. One is the ability to Slender-Walk, which, though it seems like a form of teleportation, is actually the ability to enter The Path of the Black Leaves, Slender Man's realm, where time flows differently.
They also possess the remarkable ability to ignore wounds when angry. It is currently unclear if this is because of an ability granted to them, or something else. However, Proxies who manage to escape the Slender Man do not retain this ability.