Transmogrification (sage ability)

Transmogrification is an amateur-status sage ability in the study of Outer Planes, imparting knowledge about the intricate mechanisms related to death, as the soul from the living body is transitioned into the afterlife. Each plane of existence receives the soul from the Prime Material plane after it's own fashion, involving processes that align with transcendental philosophies deriving from each supernatural culture. The essence of the sage ability includes the possibility of locating a soul that's lost forever.

Many forms of transmogrification are, expectedly, quite horrific ... but then, the only reason it matters stems from the desire of the living to restore the souls of the dead to their bodies. Some souls are bound for dark places such as the Abyss or Pandemonium (no player character, certainly), for which the transmogrification is sincerely meant to be final. Other forms, such as crossing the River Styx aboard Charon's boat, sailing the sea towards Elysium, trodding upon the Bifrost bridge or climbing to the gates of Paradise are somewhat less traumatic.

Returning the Soul

The time required for a soul to transmogrify from the Prime Material to the afterworld is 30 days. This allows time for the raise dead to return the soul to the body before the transition is complete. With resurrection, however, it's possible to return the soul after transmogrification ... meaning that the memory of being dead, for however long, is also suppressed by the spell's effect. Except that the memory can be recovered, at great cost to the individual's well-being, if that is desired.

IF either raise dead or resurrection fails, according to the standard rules of D&D and this wiki, the character is absolutely dead and cannot be raised by any known means. However, as the character's soul technically exists somewhere in the game setting, upon the plane to which it's transmogrified, it stands to reason that there must be SOME means of recovering it. The sage ability, therefore, gives the character a path to follow in order to eventually find the right tome and the right seer to explain where the lost soul is located.

The skill provides no ability to get there, nor knowledge of what the consequences of going there would be.

See also,
Contact Other Plane (sage ability)
Gate (sage ability)
Recover Soul (sage ability)