From Compendium of Worldly Lore
Duelists are skillful fighters who use their grace in battle and parry away foes. This is a good prestige class for high dex builds and stuff like that and can be slotted in with a variety of fighter like classes to give more defensive options.
Role: DPS
Characteristics: A skillful DPS who can parry, and fight enemies with grace
Source: Dungeon Master's Guide
Game Rule Information
The Duelist has the following game statistics.
Abilities: Dexterity and Intelligence, for combat skills and Constitution to help when your grace is simply not enough
Alignment: Any
Hit Die: d10
Starting Gold: N/A
Class Skills
The Duelist's class skills are Balance (Dex), Bluff (Cha), Escape Artist (Dex), Jump (Str), Listen (Wis), Perform (Cha), Search (Int), Sense Motive (Wis), Spot (Wis), and Tumble (Dex)
Skill Points at 1st Level: (4 + Int modifier) × 4
Skill Points at Each Additional Level: 4 + Int modifier
Class Features
All of the following are class features of the Duelist.
Weapon and Armor Proficiency: A Duelist is proficient with all simple and martial weapons, but no type of armor or shield
Canny Defense Ex: When not wearing armor or using a shield, a duelist adds 1 point of Intelligence bonus (if any) per duelist class level to her Dexterity bonus to modify Armor Class while wielding a melee weapon. If a duelist is caught flat-footed or otherwise denied her Dexterity bonus, she also loses this bonus.
Improved Reaction Ex: At 2nd level, a duelist gains a +2 bonus on initiative checks.
At 8th level, the bonus increases to +4. This bonus stacks with the benefit provided by the Improved Initiative feat.
Enhanced Mobility Ex: When wearing no armor and not using a shield, a duelist gains an additional +4 bonus to AC against attacks of opportunity caused when she moves out of a threatened square.
Grace Ex: At 4th level, a duelist gains an additional +2 competence bonus on all Reflex saving throws. This ability functions for a duelist only when she is wearing no armor and not using a shield.
Precise Strike Ex: At 5th level, a duelist gains the ability to strike precisely with a light or one-handed piercing weapon, gaining an extra 1d6 damage added to her normal damage roll.
When making a precise strike, a duelist cannot attack with a weapon in her other hand or use a shield. A duelist’s precise strike only works against living creatures with discernible anatomies. Any creature that is immune to critical hits is not vulnerable to a precise strike, and any item or ability that protects a creature from critical hits also protects a creature from a precise strike. At 10th level, the extra damage on a precise strike increases to +2d6.
Acrobatic Charge Ex: At 6th level, a duelist gains the ability to charge in situations where others cannot. She may charge over difficult terrain that normally slows movement. Depending on the circumstance, she may still need to make appropriate checks to successfully move over the terrain.
Elaborate Parry Ex: At 7th level and higher, if a duelist chooses to fight defensively or use total defense in melee combat, she gains an additional +1 dodge bonus to AC for each level of duelist she has.
Deflect Arrows Ex: At 9th level, a duelist gains the benefit of the Deflect Arrows feat when using a light or one-handed piercing weapon.