Ways to lower Will save?

[Skyrunner]

What I need are (preferably) secretive ways to lower will. In fact, it doesn't have to be secret: just enough so in a diplomatic situation the affected side can't offend the other side.

What's not acceptable: Crushing Despair

What I have: Inspire Awe, Wisdom damage.

Really short list >.>

[unundindur]

Fatespinner PrC from Complete Arcane :)

[Grinner]

Durkon used once Bestow Curse against a demon to accomplish this effect. I fear that usage is bit like Crushing Despair however.

[DaedalusMkV]

Bestow Curse is pretty subtle. You can cast it beforehand and deliver it with a simple handshake, high-five or pat on the back, with no obvious display or Spellcraft check to identify it and no immediately available symptoms. It can either knock down Wisdom or hit saves directly. Unfortunately, allows a Will Save to negate.

Greater Bestow Curse can nuke their Saves into oblivion, if you have it. -8 should let you do whatever you want to them, really. Also, Will Negates.

If you have access to Invisible Spell, Mind Fog is a -10. It's a somewhat obscure and totally broken feat, though, so it seems unlikely you'd have access to it. Annoyingly, Will Negates.

Touch of Idiocy causes a 1d6 Penalty to all mental stats. If you have access to 4th level slots, Empowering it has a good chance to seriously hit their Wisdom. Also hits their Int and Cha, which means that if there are multiple negotiators on the other side of the table and you roll particularly high, the fact that your target is now a drooling moron with the charisma of a stump could cause a lot of trouble.

You could try to use Intimidate to Shake them, though this seriously risks offending the other party if you don't do it very, very carefully.

Prayer could be used for another -1, but it's only one round per level and you'd either need to be really sneaky casting it or do it before the meeting, which doesn't give you much time at all.

Everything else I can think of is pretty blatantly obvious and usually involves inflicting physical damage or blasting them with rays.

Edit: If you can sneak a third-level Paladin of Tyranny or Hexblade into the meeting, that's a free no-save -2 from their Aura. -4 if you get both auras. Probably the best, most reliable and least detectable method, assuming you can find one.

[Eisenfavl]

To add on to the paladin of tyranny/hexblade: find a high Cha unseelie fey as well. Their aura is even scarier, and will stack with both of the others.

[Morph Bark]

To add on to the paladin of tyranny/hexblade: find a high Cha unseelie fey as well. Their aura is even scarier, and will stack with both of the others.

Only if the Unseelie Fey has the Winter aspect, but yes. An Unseelie Fey [race X] Paladin of Tyranny or Slaughter 3/Hexblade 4 with Dark Companion/Blackguard 3 is decently strong in melee, a great save-debuffer and has high saves himself.

[Acanous]

pretty sure there's a bard variant somewhere that debuffs saves with bardic music.

[SowZ]

Using a method to lower someones will save that, itself, allows a will save is really silly to me.

[Ranting Fool]

Using a method to lower someones will save that, itself, allows a will save is really silly to me.

My brother got angry by that very point the other week:P

Not a spell but i'm sure there are some poisons that would lower wisdom... maybe share a nice meal then just still+silent zap someone :P

That or just get your friendly rogue to stab them before you zap:)

What about slipping them a cursed item... "Oh you are so damn awesome here is a gift to prove how awesome I think you are... yes yes just put on the crown of awesome"

[Eonir]

Not sure how subtle it would be, but you could always summon Allips (http://www.d20srd.org/srd/monsters/allip.htm) and have them drain wisdom.

[rot42]

Insidious Suggestion from Races of Eberron page 187 casts a Suggestion every round until they fail. Sorcerer/Wizard 5, Bard 4.

Voice of the Dragon in Spell Compendium page 232 gives a long-lasting bonus to your social skills and can be discharged for a Suggestion effect. It is not specified how much wiggling your toes is necessary for the discharge effect. Bard 4, Dragon 4, Sorcerer/Wizard 4.

Doomspeak from Champions of Ruin page 20 gives a hefty debuff for one round, but requires Bardic Music and Will negates.

For casting while negotiating, look to the skill tricks in Complete Scoundrel. Particularly False Theurgy (why sure, of course this is just a harmless spell I am casting on you) and Conceal Spellcasting (Sleight of Hand vs. Spot). Beguilers (PHB II) get Silent and Still as bonus feats and a bunch of skill points. A Bard can also get an ability to cast while performing with none the wiser.