Crit Threat Range - Expanding

[halfgiant]

Spell

Duo-Dimensional Weapon
Psychoportation
Level : Psion 4 / PsyWar 4
Display : Vi
Manifestation Time : 1 action
Range : Personal
Target : One of your held weapons
Duration : 2 rounds/level
Power points : 7

Your weapon’s edge becomes two-dimensional, making it infinitely razor-sharp. Almost any hand-held weapon can be altered with this power, even bludgeoning weapons such as hammers or maces. Only jointed, chain, or rope weapons (such as whips, flails, or nunchuks) cannot be made into dimensional blades. However, bludgeoning weapons will do slashing or piercing damage (damage dice as normal). In addition, the critical threat range is increased to 17-20; however the damage multiplier remains that of the weapon.
This power’s effect can be used to breach stoneskin spells and Kinetic Barriers. While this power is in effect, the psionicist’s weapon ignores any armor worn by the victim - only Dexterity and magical protection applies. In the case of monsters, the DM must decide if the creature’s Armor Class is due to thick, armor-like hide or natural quickness.
The dimension blade can also be used to cleanly sever inanimate objects, such as an opponent’s weapon, a stone pillar, or the axle of a wagon. Any object struck by a dimension blade must make a fortitude saving throw or be sliced in half.

Feat

Improved Critical
( Player’s Handbook v.3.5, p. 95)

[Fighter Bonus Feat, General]

Choose one type of weapon, such as longsword or greataxe. With that weapon, you know how to hit where it hurts.

Prerequisite
base attack bonus +8, Proficient with weapon,

Benefit
When using the weapon you selected, your threat range is doubled. For example, a longsword usually threatens a critical hit on a roll of 19-20 (two numbers). If a character using a longsword has Improved Critical (longsword), the threat range becomes 17-20 (four numbers).

Special
You can gain Improved Critical multiple times. The effects do not stack. Each time you take the feat, it applies to a new type of weapon. This effect doesn’t stack with any other effect that expands the threat range of a weapon (such as the keen edge spell). A fighter may select Improved Critical as one of his fighter bonus feats (see page 38).

Weapon Enhancement

Keen
Enhancement
(Dungeon Master’s Guide v.3.5, p. 225)

Price: +1 bonus
Property: Weapon
Caster Level: 10th
Aura: Moderate; Transmutation
Activation: —

This ability doubles the threat range of weapon. For instance, if it is placed on longsword (which has a normal threat range of 19-20) the keen longsword scores a threat on a 17-20. Only piercing or slashing weapons can be keen. (If you roll this property randomly for an inappropriate weapon, reroll.) This benefit doesn’t stack with any other effect that expands the threat range of a weapon (such as the keen edge spell or the Improved Critical feat).

Prerequisites: Craft Magic Arms and Armor , Keen Edge .