DC 100 Sense Motive

[Piggy Knowles]

I'm putting together a build that relies on consistently making a DC 100 Sense Motive check to sense surface thoughts. That said, I'm having trouble reliably making the check. The build is pretty flexible; the only thing that can't change is the base race (changeling). I'm also trying to refrain from Item Familiar or a +30 item. I also don't want to rely on Guidance of the Avatar, because I want to be able to do this in combat without having to first spend a round cast GotA.

So... can anyone figure out a way to put together a changeling that can reliably make a DC 100 Sense Motive check, without using Item Familiar or a +30 item, or Guidance of the Avatar? With incarnum I can reliably get into the seventies, but that's the highest I've gotten.

[Dread_Head]

An Unseelie Fey Magic Blooded Venerable Changeling at level 20 will have an Int and Cha score of:
Int = 18+3(venerable)+6(enhancement)+5(inherent)+6(abili ty boon)=38 for a +14 modifier.
Cha = 18+3(venerable)+4(racial)+5(level up)+4(inherent)+6(enhancement)+6(ability boon)=44 for a +17 modifier.
Take Keen Intellect for Int to Sense Motive rather than Wis.
Go Changeling Rogue 1 / Marshal 1 / Incarnate 4 / Chameleon 10 / X4.
Take the feats Able Learner, Keen Intellect, Skill Focus, Negotiator, Expanded Soulmeld Capacity and Bonus Essentia.
Changeling Rogue lets you take 10: 10
Max ranks at level 20: 23
Int Modifier: 14
Cha Modifier: 17
Racial: 2
Negotiator: 2
Skill Focus: 3
Truthseeker Goggles (6 essentia): 14
Suspicious and Illiterate traits: 2
Total: 87
MW Tool (I have no idea what this would be): 2
Total: 89
Then you only need a +11 item. There's 4 class levels to play around with there and at least 2 feats, 4 if using flaws but I can't see any way to do better than that at the moment.

[sleepyphoenixx]

Exemplar 1 grants a +4 competence bonus. Greater Heroism adds a +4 morale bonus to skill checks and is relatively long term.
Blade Meditation(ToB) adds another +2.

[Slipperychicken]

You could probably get a similar effect with several overlapping continuous Detect Thoughts spells, the main differences being you'd have to wait two rounds and there would be a tiny failure chance. Each saving throw the target needs to make will reduce his chance to succeed. If you get enough of them going at once, the target will be basically guaranteed to fail at least one of those saves.

With multiple iterations of detect thoughts, the chance for your target to succeed every save will be = P^N, where P is the probability (represented as a number between 0 and 1) for your target to make his save against a single iteration, and N is the number of detect thoughts effects running at once. Obviously, this means that your target's chance to fail at least one save = 1-(P^N).

Let's say that we wanted a character who can make the save on a 2 (that is P=0.95) to have a chance to succeed <1%, we'd need roughly 90 iterations of detect thoughts(0.95^90 =~ 0.0098). Stacking them all onto the same item (say a Helm of 90x Detect Thoughts) would have a base price of 549,000gp, but it would be a simple matter to get that price down to a reasonable level with cost-reducers (http://brilliantgameologists.com/boards/index.php?topic=7274.0) (even just crafting it yourself would bring it down to 274,500gp). And of course, you can always add additional Detect Thoughts iterations for 6000gp each if you feel like the "failure" chance is too high.

So yeah, such an item would allow a small failure chance, but would consume far fewer build resources such as levels and feats, freeing up said resources for other priorities such as spellcasting and combat effectiveness.

[Irk]

If you are going to buff sense motive, Baffling Defense (ToB P. 70) makes your AC equivalent to a sense motive check as an immediate action.
Let's see how high it can go.

+2 racial bonus from changeling, so a good base, hellbred is the only other I know of that has that with an LA of +0, but there are probably more. Plus,
changelings are just really good.

The Mind Domain gets +2 untyped (Cloistered Cleric, maybe?)

A bronze Medalion of Io will give another +4 untyped for 1,000 GP. (RotD 125)

An affiliation score 0f 4-11 with Fharlanghn’s Way, the Protection Domain, or Correlon Larethian will net you another +2. This will count as +4, as you could net the domain one and then one of the deity ones. (CC chapter 1)

Since detect surface thoughts can be opposed by a bluff check, you can use Psionic meditation + Inquisitor (XPH 42) to get a +10 untyped bonus on the check.
If you do go the Psionic route, you could get Psicrystal affinity and use the sympathetic personality to get another +3 untyped bonus, and you could use Psicrystal containment to store the focus for Inquisitor. The Attraction (XPH 78) power gives another +4, but I'll shelve that since it's unreliable and is not technically all day.

One power you DO want is Detect Hostile Intent (XPH 91), which grants you the ability to make sense motive checks as a free action on anyone within 30 feet for it's duration. And it lasts 10 minutes per level.

A Marshal’s Motivate Wisdom gives +CHA to the check.

That comes out to +25+CHA+WIS+ranks, which is not too great.

Silvertongue Mask bound to brow chakra with an Incarnum focus is +16 insight, +18 with Expanded Soulmeld Capacity.

Exemplar + Skill Focus gives +7 and the ability to take 10

At level 20, our ranks will give +23
Wisdom will likely be 18 +5(Inherent) +6(Item) for +9
Charisma could Also be 18 +6(Item) +(5 Inherent) for +9

So, to summarize.
Changeling Incarnate 17/Cloistered Cleric 1/Marshal 1/ Exemplar 1
Feats: Psionic Meditation, Inquisitor, Psicrystal Affinity, Expanded Soulmeld Capacity, Skill Focus leaving you with 4 other feats to pick, if you use flaws.
BONUSES
+2 Changeling
+2 Mind Domain
+4 Fharlanghn’s Way and Protection DOmain affiliations
+10 Inquisitor
+3 Sympathetic Psicrystal
+4 Bronze Medallion of Io
+9 Morale Motivate Wisdom Aura
+9 Wisdom
+18 Insight Silvertongue Mask
+3 Skill Focus
+4 Competence Skill Artistry
+23 Ranks
TOTAL: +91. Take 10 and you get 101.


With A Dorje of Detect Hostile Intent, this becomes turns into the ability to detect the surface thoughts of everyone you see instantly.
Hope this helps.