Whether Lethe was intended as a product or a more natural result of a Great dragon's passing is hard to say.
As far as the continuity with Earthdawn is still a thing, no, I don't think it could be considered as something "natural." There was a precedent with Yuichotol spirit, that at the time did not seem to be the norm.QUOTE
The Book of Dragons
The most intriguing of Icewing's spirit allies is the one Named Ghost Scales. I strongly suspect that this is in fact the spirit of the Yuichotol, killed by the Therans before the Scourge. Yuichotol mated with Icewing on more than one occasion, and she was as adept in manipulating spirits forces as he is. Together they endhanted a set of powerful soul-stones, similar to those used by the nethermancers of the Hold of Courage in ancient Cara Fahd, so tha if one should die, their spirit would remain trapped within the stone. This transgression of dragon customs has yet to be atoned for. Her current state and powers are unfathomable to me, but I understand he has several magical constructs which allow her to speak and move. I would grieve to discover that one so great as she had sunken to become merely another doll of his.
- The Outcast Dragon, to the Denairastas
I understand there exists a difference of opinion on this matter between Doll-Maker, Ghost Scales and myself on one hand and many others on the other. May I remind you that at the last Council we allotted Ghost Scales a period of peace which she has not yet exhausted. Once that time has ended, we shall revisit the matter.
- Dunkelzahn, to the other dragons
Since The Clutch of Dragons tells us Lofwyr tried to destroy the spirit of Ghostwalker's mate and fragmented it several thousand years before the Sixth Age, it kinda hints at what got out when the dragons did "revisit the matter."
The most intriguing of Icewing's spirit allies is the one Named Ghost Scales. I strongly suspect that this is in fact the spirit of the Yuichotol, killed by the Therans before the Scourge. Yuichotol mated with Icewing on more than one occasion, and she was as adept in manipulating spirits forces as he is. Together they endhanted a set of powerful soul-stones, similar to those used by the nethermancers of the Hold of Courage in ancient Cara Fahd, so tha if one should die, their spirit would remain trapped within the stone. This transgression of dragon customs has yet to be atoned for. Her current state and powers are unfathomable to me, but I understand he has several magical constructs which allow her to speak and move. I would grieve to discover that one so great as she had sunken to become merely another doll of his.
- The Outcast Dragon, to the Denairastas
I understand there exists a difference of opinion on this matter between Doll-Maker, Ghost Scales and myself on one hand and many others on the other. May I remind you that at the last Council we allotted Ghost Scales a period of peace which she has not yet exhausted. Once that time has ended, we shall revisit the matter.
- Dunkelzahn, to the other dragons