I know what you mean though. And yes, it's near-impossible to pin down.

Anyway that multilayeredness was one of the reasons I enjoyed writing 'My Immortal' so much. Because if anyone's an expert when it comes to 'centuries-old guys with a dark past who may or may not be evil' it's Buffy... But, it was the layers that made it interesting, the way Jack let Buffy glimpse different sides, different parts (sometimes on purpose, sometimes by accident), and I loved writing that story way, way too much. *sigh* I sometimes think I could write Jack forever.