We know that Lashiec was revived for PSIV and we've had speculation on the question of Zio's possible revival. Both revivals would/could happen because those guys served Dark Force. Now, let's take it a step further. Let's look at Medusa.
In PSI, we're told that Medusa had been defeated by Perseus long ago and has just recently revived. Since she guards one of the Laconia weapons that Lashiec fears and dead people don't revive on their own, it's safe to think that this was the work of Dark Force.
So, here's my question for you. Was Medusa a servant of Dark Force in her original life, long before the time of Lashiec and Alis? Was she revived as part of pact with DF, like Lashiec was later?
I think she may have been, but I'll see what some of you have to say before going into my reasons and thoughts on the subject.