Can you threaten a crit on a 2? [duplicate]

Question

There's a fair number of feats and features which increase a weapon's range to threaten a critical hit in 3.5. Off the cuff, a Fighter with a falchion and the Improved Critical feat threatens a crit on a 15-20, but I have a limited amount of 3.5 knowledge and am all but certain it's possible to get a much larger range. Could you threaten on a 2?

I'm curious as to what the maximum critical threat range is presuming the following restrictions:

• 20 levels (i.e. no Epic Handbook or deity stuff)
• No outside help
• Ideally repeatable within the same combat (i.e. if a spell increases the weapon's crit range, it's not a one and done type of effect; something that doesn't expend a resource like spell slots is even better)
• No pun-pun

Answer 1

Using un-updated 3.0e material

Prior to the “v.3.5 revised edition,” critical effects usually stacked, which made it quite possible to achieve a 2-20 critical threat range. This was one of the big things they changed in the revision. Almost everything that affected critical threat range was explicitly updated to nix stacking.

However, under the rules for using 3e material in a 3.5e game, the disciple of Dispater prestige class from Book of Vile Darkness remains legal and un-updated. Its iron power ability triples threat range, and explicitly stacks with Improved Critical (but not keen). This is (arguably, at least) more specific than 3.5e Improved Critical’s statement that it doesn't stack with anything, since iron power addresses Improved Critical specifically.

Realistically, though, the guidelines for 3e content in 3.5e call on the DM to update un-updated stuff. So in practice, they wouldn’t stack.

With an 18-20 weapon, iron power achieves 12-20 threat without Improved Critical, or 9-20 threat with it. However, there are a couple of 17-20 weapons out there (stump knife from Arms & Equipment Guide, which has all kinds of limitations, and bladed gauntlet from Sword & Fist, which does not but was errata’d to 19-20), and there is also the streetfighter barbarian ACF which increases critical threat range by 1 when charging or attacking a flat-footed foe (and that’s straight 3.5e material). Combined, a stump knife with streetfighter, Improved Critical, and iron power achieves a critical threat range of 1-20, though of course you still have to hit, which you won’t on a 1.

With sniper

As discussed in this answer, a targeteer fighter from Dragon vol. 310 can use the sniper ability to trade attacks for critical threat range increases. Get enough attacks—probably using natural weapons—and you’ll reach 2-20. Iron power will definitely help you get there more easily, even if updated to not stack with Improved Critical.