Reading tons of guides on several classes, many touch on an interesting route of debuffing, namely fear-stacking. However, other than other bonuses in 3.5e, it is not clear to me which fear effects stack and which don't. I play a Dread Necromancer, and want to know if Fear Aura stacks with itself.
From Heroes of Horror, pg. 86:
Fear Aura (Su): Beginning at 5th level, a dread necromancer radiates a 5-foot-radius fear aura as a free action. Enemies in the area must succeed on a Will save (DC 10 + 1/2 her class level + her Cha modiﬁer) or become shaken. A creature who successfully saves cannot be affected by that dread necromancer’s fear aura for 24 hours.
This basically means that, as long as the creature fails its save, you can keep spamming your Fear Aura on them, but does it stack with itself? How can I see if a source of Fear stacks with other sources, or itself? Would it stack with, for instance, Intimidate?