For a second he couldn’t tell where he ended and the world began, as clawing fingers from elsewhere reached out and caressed the Mark of the Outsider that blazed in blinding glory behind Corvo’s closed eyes.

So I will take this from The Corroded Man and throw it into Corvo the Black AU yes? Yes. Imagine that everytime Corvo uses the mark it feels like someone is touching his hand, and the more he reaches into the Void, the more The Void reaches back.