In short: The blade is master at performing with a weapon, especially blades. If there is a showy way to wield, throw, or perform with a weapon, a blade knows how to do it better than anyone. By performing a Weapon Display, he reduces the morale of opponents by 2 and increases his allies to hit rolls by +1. Blades are considered ambidextrous and can use weapons in both hands, only suffering a -2 penalty to hit with their off-hand.
They may also perform a Defensive Spin, which reduces the blade's armor class by a number equal to half of his level and does a similar amount of damage to the attacker (if they don't save), or an Offensive Spin, which scares the opponent. Unlike other bards, blades do not gain the 10th level ability to use written magical items.
Requirements: Dexterity: 13, Intelligence: 13, Charisma: 15
Description: Blades are master artisans with bladed weapons. Everyone has seen a Blade in action at fairs and carnivals. They are the knife throwers who pop balloons while blindfolded and swallow slender sabers such as those wielded by lawless pirates on the high seas.
Blades also perform amazing displays of weapon skill and control as they flash various weapons all about their bodies with deadly precision. Oriental Blades are perhaps the most skilled at this particular art form. Using weapons such as the three-piece rod, nunchaku, or the katana, Oriental Blades put on amazing displays of rapid weapon movement, including offensive and defensive spins, katas, and ritual dances.
Besides rapid displays of weapon skill, Blades also perform slow, elegant dances, involving incredibly precise movement and timing. These dances include thrusts, lunges, leaps, graceful arcs, etc.
If there is a showy way to wield, throw, or perform with a weapon, a Blade knows how to do it better than anyone.
Weapon Proficiencies: At least half of a Blade's weapon slots must be selected from the following: Sword (any), dagger, knife. Blades are also limited to expanding but one slot on a purely missile weapon.
Armor/Equipment: To complement their entertainment image as mysterious and fearsome men, Blades often dress in black garb, even going so far as to wear masks, facial wraps, or black headgear. Their weapons are always kept in perfect shape. A man dressed in solid black, flashing gleaming silver blades, is truly an awesome sight.
Weapons Display: For this ability to have an effect, the Blade must whirl a non-missile weapon about his body. The observer must be close enough to the Blade to see the display. The display has no effect on those already in combat, as they are too busy to notice.
By whirling a melee or hurled weapon about, a Blade can affect the morale and courage of others. Such a display of skill, precision, and deadly grace lowers opponents' morale by 2 and inspires allies, giving a +1 bonus to allies attack rolls.
The display must occur for a full round without interruption. During this time, any successful attack upon the Blade, or failed save by the Blade, disrupts the display.
The display may only be used once per encounter; the display lasts for one round per level of the Blade.
This ability requires a lot of room (it cannot be done in a narrow corridor). Specifically, the Blade must be able to stand with his arms extended while holding out his weapon and be able to move his arms in all directions without contacting any obstructions.
Handle Weapons: Blades train and perform with weapons in both hands. Blades can wield 2 weapons with a reduced penalty, no penalty on the main weapon, and only a -2 on the off hand.
Trick Throw: Although this ability is called "Trick Throw", it functions the same for both missile weapons and hurled weapons. This allows Blades to perform called shots. The normal -4 penalty is lessened by -1 for every 5 levels.
Defensive/Offensive Spin: These are both elements of a good weapons display. They also have other uses as described below:
The defensive spin is a specialized form of the parry. The blade whirls his weapon to create a deadly shell about his body. A Blade may not attack during the spin. The AC of the Blade is lowered by half the Blade's level.
In addition, any creature that makes a successful melee attack against the Blade must roll a save vs. paralyzation or suffer damage equal to half the Blade's level. The spin lasts for a maximum number of rounds equal to the Blade's constitution. A successful hit ends the spin.
The offensive spin is a much more threatening maneuver. The Blade creates a fearsome looking display of skill directed at a specific opponent. The spin must last for the entire round, during which the Blade does not attack. On the next round, the Blade makes a normal attack roll. Of this hits, the victim must roll a morale check or stay at least 10 feet from the Blade. This may be attempted only once per opponent.
Furthermore, the Blade must not have been damaged by that creature in combat. This is a difficult condition, because they get the free round to attack while the Blade prepares to do this maneuver.
Blades do not get the ability to use scrolls at level 10.
Source: The Complete Bard's Handbook