Not One Allegiance
Dark Templars are associated with Shadow, but they do not all stand in the same relationship to it. Some knowingly serve powers of the Dark Horde. Some may be manipulated by intermediaries. Others pursue personal ambitions while believing they can use Shadow without becoming its servant.
Baara, earthly embodiment and chief agent of Dral'gath, is a power to whom a Dark Templar might ultimately be drawn or bound, but not every fallen Guardian begins as Baara's conscious servant. The deeper paths by which Shadow claims, communicates with, or commands the fallen are reserved for Game Canon.
Wights and Other Hidden Threats
The existence of concealed servants of Shadow makes certainty dangerous. A Guardian may be corrupted by choices or supernatural influence; other Shadowborn threats may work through hosts of their own. These phenomena should not be treated as interchangeable, and their deeper distinctions belong in Dark Horde lore.