Two Weapon Fighting

Usage: Passive
Prerequisite: Dexterity 15

Description

Two Weapon Fighting reduces the to-hit penalty when using two weapons at the same time.

The penalty for your primary hand lessens by 2 and the one for your off-hand lessens by 6, so it becomes -4 (main hand) / -4 (off-hand) (instead of -6/-10 without this feat).
If the off-hand weapon is light, the penalties both decrease by another 2 points, down to -2/-2 (instead of -4/-8 without this feat).
For wielders of non-light weapons, Oversized Two Weapon Fighting was once recommended to bring their attack penalty down to -2/-2, but with the current game math, this is not necessary (or still recommended) - there are better feats to take.

After Update 5, an off-hand attack would have a chance to proc on any main hand attack now, instead of being predetermined on certain attacks. The default chance to proc an off-hand attack is 20%.

Two Weapon Fighting increases the chance to proc an off-hand attack by 20%, bringing the total chance to 40%. Additional TWF feats increase the percentage chance of proccing an off-hand attack by 20% per feat, to a max of 80% with Greater Two Weapon Fighting.

This feat also works for Handwraps users.

Additional chances to proc off-hand attack

Tempest enhancements, second and fifth core ability - 2x +10%
Shintao enhancements, Deft Strikes and Meditation of War (in Wind Stance)
Vistani Knife Fighter enhancements, Double Daggers - +20% (daggers only)
Raid weapon set with two Brilliant Crescents - +20%
Forest's Versatility - +5%

There's no benefit of having more than a 100% off-hand strike chance.

Hits with a TWF character's offhand weapon only receive half of the applicable Ability bonus to damage.

Notes

TWF provides no benefit to the use of thrown weapons.
TWF provides no benefit to the use of two ranged weapons - in fact, it is not possible to wield two ranged weapons simultaneously in DDO - but see Inquisitive enhancements.
A ranger is automatically entitled to Two Weapon Fighting at 2nd level, even if he does not have the prerequisite for it.
Single Weapon Fighting is mutually exclusive with Two Weapon Fighting.
Fighters may select this feat as one of their fighter bonus feats.
Monks may select this feat as one of their martial arts feats.

Feat	Requirements	Offhand Strike Chance (Cumulative)	Other Benefits
Two Weapon Fighting	15 Dexterity	40%	Attack penalty reduced to -4/-4 from -6/-10 (Attack penalty reduced to -2/-2 if offhand is a Light Weapon)
Improved Two Weapon Fighting	6 BAB, 17 Dexterity	60%	N/A
Greater Two Weapon Fighting	11 BAB, 17 Dexterity	80%	N/A
Perfect Two Weapon Fighting	Level 26, Epic Destiny Feat	N/A	+5% Doublestrike +10% Offhand Doublestrike
Oversized Two Weapon Fighting	12 Strength, Two Weapon Fighting	N/A	Attack penalty reduced to -2/-2
Two Weapon Defense	Two Weapon Fighting	N/A	+2 DR when actively blocking and dual-wielding. +1 AC, +5 PRR and as +10 MRR cap when dual-wielding.

Two Weapon Fighting