A very old name, from the 16th century, Scottish in origin, meaning "from the dark river." A man who has deep insights, mystical powers and isn't afraid to explore both the dark and light sides of life, seeing them as all one. A person of great understanding, having wisdom that accrues with age. Very public persona, but deeply private in many ways.
"Don't bother trying to fool, outwit, or fully understand him, man. He's a Douglas---sees all, knows all, confounds all."