Oh, wow! I read some of Spider-Girl years ago, and I didn't really know anything about Daredevil, but I always thought Darkdevil was just Ben Reilly (the spider clone) for some reason dressing up as DD. I had no idea he was also (?) Matt's ghost.

Darkdevil was kind of Spider-Girl's mentor, and I remember he was always kind of a dick to her. Like, not cruel but he antagonized her as a way of motivating her. I guess he was copying Stick's teaching style a little. xD