1% Chance of Ghost Spawn

[Dualblade]

I'm just waiting for her to be a final boss for a raid. Totally gonna happen, calling it now.

[Kuurei]

I'm just waiting for her to be a final boss for a raid. Totally gonna happen, calling it now.

Edda and a wave of like 600~700 skeletons? Sounds fun.

[Cherie]

I'm just waiting for her to be a final boss for a raid. Totally gonna happen, calling it now.

but but... wouldn't it make sense that she becomes a vendor for some rare item you need to make the relic in 3.0? lol

I can see the people camping her for 6+ hours, just to run over to her to have her vanish before you can buy the item you need. :x

Sounds about right? lol

[Grimmel]

The game has shown the ability to make NPC's appear in the open world based on individual players progression. Like the Doman refugee's in Mor Dhona. If you didn't catch up to that point in the story then they wouldn't appear around town.

I believe this to be untrue. The first video we'd ever seen of someone spotting Edda was most likely a low level. It was a Lalafell in the starter gear (see first video posted in OP). Unless this individual comes forward we can assume he was a low level.

She probably uses the same mechanism that has retainers appear at random times. Found out that those are only visible to you when they spawn.

I'll have to test this. I have two accounts so one day I'll park them in Gridania where she spawns and wait.
She seems to only appear at 2:00 AM in game time for two seconds before disappearing.