We all know that Soulblighter used Tramist's Mirror to bring back Shiver's soul from the dead. But is this also what the fallen lords used to bring back shades? I think so for the following reasons:
1) Shiver and Shades float in the same way, toes pointing down, steady float (unlike the wabling souless), with a large eyrie shadow under them.
2) a- Shiver is a spirit of a dead Fallen Lord (dead magic wielder)
b- Shades are spirits of dead Avatars (dead magic wielders)
Im sure Forrest will be he momentarily to prove me wrong, or right =)