Fortification and Feat

[Borthos]

The dread necromancer class grants Fortification up to 75%. There is a feat in Libris Mortis called Tomb Born Fortitude: "You have a 25% chance to resist critical hits. When a critical hit or sneak attack is scored against you, there is a 25% chance that the critical hit or sneak attack is negated and damage
is instead rolled normally."

Would this stack to give me 100% fortification, or would it overlap like SR and cause two "fortification checks?"

Edit: And, are Summon Undead Spells considered Necromancy or Conjuration?

 

[Dandu]

1. I suspect it overlaps
2. Summoning seems to be Conjuration's thing in 3.5

 

[Borthos]

I know summoning is Conjuration for Summon Monster/Nature's Ally, but in the PHBII, dual school spells were introduced, so could those fall under dual school?

 

[Dandu]

Conjuration, Summoning, [Evil]

 

[Submission]

I'm pretty sure dread necro gives you light fortification and thats 25% at lvl 10 and thats all.

and

2. summon undead is on a dread necromancers spell list anyway so fear not

 

[Borthos]

I'm pretty sure dread necro gives you light fortification and thats 25% at lvl 10 and thats all.

and

2. summon undead is on a dread necromancers spell list anyway so fear not

1. Actually, dread necro gives [edit] 50% at 17th
2. Yeah, i know, it would just make sense if it was also of the necromancy school b/c it is undead after all

Edit 2: The Quickening: If I bought armor that had medium fortification, would it also overlap? The ability from dread necro states it acts like light fortification, so would it stack or still just overlap?

 

[Submission]

The armor enchant would overlap your dread ability though this is a gray area where the Dm would have say.

I say this because the dread necromancer ability effects the dreadnecro not the gear and it probably applies to the body in the 'hardening process for lichdom in the future (same as the natural DR you get). Though you could argue its a force effect that acts like mage armor in which case you could argue it.

 

[Borthos]

What about the undead graft that offers 25% fortification?

 

[Submission]

What book is that from cause i'm not quite familiar with it?

edit: Undead Skin Libris Mortis pg 80

Undead Skin: This mottled gray hide grants the grafted
creature 25% resistance to critical hits and sneak attacks, similar
to armor of light fortifi cation. This resistance doesn’t stack with
similar abilities.

 

[Jhaelen]

Would this stack to give me 100% fortification, or would it overlap like SR and cause two "fortification checks?"

AFAIK, _nothing_ will give you 100% fortification. It's capped at 75%. Even if you found something that appears to stack by RAW (and your DM is foolish enough to allow it), you'd have to mutiply the different kinds of fortification, i.e. your first fortification source would cause damage to be reduced by half, the second source reduces the remaining damage by another 25%, etc.