Shadows Wiki

When asked for a biography, Marcus Whitby supplied this:

The origins of Marcus are unclear, obscured by myth and legend. Many believe that his blessed birth, the result of a romantic tryst between a ancient god and a mortal, occurred in Whitby; a small British town renowned for its supernatural legacy. Moments before his birth, it is said that planets aligned, blotting out the sun, casting the world in etherial shadow as if nature itself was declaring deference and respect for the oncoming storm. No one knows of his childhood, perhaps in his early years his unrestrained power and charm would not allow written words to capture his radiance and thus once pen was put to paper, words could not flow.
He appeared in Boston on the eve of a full moon flanked by two large griffins with he himself riding on the back of the great ebony dragon. The sky, stained blood red and crimson, crackled with lighting at his very presence. There it is written, that is when he saw the progeny of Shadows and wept compassionate tears at their plight. He took mortal form and guided them into greatness, only to disappear as quickly as he had come.

Subsequent inquiries indicate that he may, in fact, be a British subject who works in post-production.

Marcus crewed several episodes of Shadows, including "The Agency", "Trust of the Fallen", and "Salesman", and made several appearances as an unnamed Agent. He directed "Pest Control".