On the Knights of Noromath server, the Shadow Weave is supported in a few specific ways. This page is intended to describe the advantages of using the Shadow Weave Feat.
The Shadow Weave is a hidden, opposite magical apparatus to Mystra's Weave. In truth, the Shadow Weave hides in the empty spaces between the lines of Mystra's Weave, where it attempts to subvert the power and usage of the Weave to one day replace it.
Once a character has discovered the knowledge of the Shadow Weave by selecting the Shadow Weave Feat, they are at once considered to always be using the Shadow Weave from that point forward. All of their spells, potions, and any other spell-like effects are now using the Shadow Weave.
A character with the Shadow Weave feat casts spells from the enchantment, illusion and necromancy schools at +1 caster level. A character with the Shadow Weave feat can cast spells with the light descriptor, but these only last for 1 turn at maximum duration.
After the Time of Troubles, the massive extent of "Helm's Legacy" or "Dead Magic Zones" can only be described as damage to the Weave. Dead Magic Zones can be as large as a palace but many are only the size of a closet. If the local Weave is damaged, spells will fail inexplicably. Only a successful Spellcraft roll against difficulty 25 will confirm the existence of a Dead Magic area.
Those with the Shadow Weave Feat may cast spells without any difficulty in a Dead Magic zone. Those who are clerics of Mystra may also cast their spells without difficulty, but that is a special trait of Mystra's clergy. Paladins of Torm receive no special ability to cast spells in a Dead Magic Zone, but like the Mystran Clergy, each attempt to use magic is considered to "mend" the local Weave by a small amount.