Netherworld knowledge

Netherworld knowledge was the in-depth field of study of the Outer Planes,  how they related to Toril,  and the afterlives within them.

Knowledge
Those who specialized in this field could generally identify extraplanar creatures, such as baatezu and tanar'ri, and were knowledgeable of their behaviors. They could also potentially identify the weaknesses or natural defenses of such creatures.

History
This field of study dated as far back as the Netherese Empire, where it was studied by the doomscribes of Jergal.

Individuals

 * Sammaster was quite skilled in this field.

Religions
A variety of specialty priests in the Realms that were devoted to deities of death were well versed in this field of study. These specialty priests included the following:
 * Divine arbitrators, a variety of specialty priest in the Church of Osiris.
 * Doomguides, a variety of specialty priest in the Church of Kelemvor.
 * Doomscribes, a variety of specialty priest in the Church of Jergal.
 * Gray ones, a variety of specialty priest in the Church of Myrkul.