Tunnelfighter

(Underdark, page 27, DnD 3.5)

[General]

You can fight more naturally in the cramped and close quarters of caves and tunnels than usual.

Prerequisite

Tunnelrunner (or), DEX 13

Benefit

You ignore the penalty for hampered melee when fighting in a narrow space (an area smaller than but at least one-half of your space) or a low space (an area shorter than but at least one-half of your height) with light or one-handed melee weapons. Furthermore, you take only a --4 circumstance penalty when using a two-handed weapon in such conditions. In a space both narrow and low, you function as if only one of those conditions applied (see Chapter 7: Exploring the Underdark for rules on fighting and moving in cramped spaces). In addition, when fighting in cramped quarters, you do not lose your Dexterity bonus to Armor Class.