I am rather disappointed on the lack of information surrounding this mob. No one really understands exactly what spawns her or where to find her, there are just estimates here. I would think that the sword would have been a little more important in days long ago, and as such pulled more user input. Trouble is, alot of people browse, but don't post, so I guess I'll at least include this observation for others to utilize.
As for the Crypt.. it's a night spawn situation here, which is leading this necro to believe that she also spawns at night.
I have been in the zone for 2 days studying their behavior. Today i noticed that at 6pm game time, there were un-targetable placeholders in the spots where skellies normally spawn throughout the Crypt.
At 7pm game time all of these PH's pop out and the crypts are empty. Then, at 10pm game time the targetable versions are here, and sometimes the named that spawn here is also up, which is not even listed above.
At 5am these skellies will stop spawning and the un-targetable PH's will return once more.
This does not seem to affect the spawning of skellies outside of the Crypt as they can be up pretty much any time.
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Now, as for her.. I found her up finally today about 1am game time in a static spawn at this location - -2075, -60.30, just outside of the little city area in what appeared to be an undead spawn point. She was of course utilizing the sword, but dropped the mask and a worthless weapon. This is a different location then any of the above, so I'm quite positive that she spawns somewhere, anywhere in the zone, in some type of undead PH spot. I will update this post if I encounter any new information. Best of luck, she's a long spawn :-(


Pestilence
Veil of Plagues
Veil of the Plaguecaller