Detect Shadow Weave User

(Champions of Valor, page 28, DnD 3.5)

[General]

You can determine if a magic item or spellcaster is using the Weave or the Shadow Weave.

Prerequisite

Knowledge (arcana) 5 ranks, Spellcraft 5 ranks

Benefit

Whenever you observe spellcasting or a magical effect you can make a Spellcraft check (DC 15 + spell level) as an immediate action to determine if the effect comes from the Weave or the Shadow Weave. When using detect magic, you automatically identify the Weave or Shadow Weave origin of any aura you detect.