Improved Two Weapon Fighting

This feat gives adds additional off-hand attack hook on your 3rd attack in the combat chain. This attack is at a +5 bonus to-hit (just like your 3rd main-hand attack). Off hand hooks always happen on the 2nd and 4th attacks regardless of feats.

This feat also works for unarmed Monks much the same. Some developer verification of this was posted by Eladrin on the US forums.

This brings the total number of attacks with Greater Two Weapon Fighting to: as posted by [Eladrin] in the DDO Forums

All Classes Except Monks

Monks

Rangers with the Tempest III Prestige Enhancement

Prerequisite: Dexterity 17, Base attack bonus of +6 or higher, Two-weapon fighting.

A fighter may select this as one of his fighter bonus feats.

A ranger receives this feat automatically at level 6 even without meeting the prerequisites.

Related Feats:
 * Two-weapon fighting
 * Greater two-weapon fighting