A thief who possesses a magical cane, one that gives him the ability to control darkness, and later is reimagined as an immortal being with the ability to transport himself over vast distances. He can use the darkness as a shield, or create whole areas of it, and possesses the ability to summon demons from another dimension. While parts of his story may be too convoluted for TV, there is plenty that they could use that would make him work as an extremely formidable foe for The Flash, one who could recur throughout the season, or be seeded as a potential big-bad later down the line.