Command Style

Unreleased The Command Style is a new battle system that appears in Kingdom Hearts Birth By Sleep. Terra, Aqua, and Ventus have times when the Command Bar at the top of their Command Menu fills up after hitting enemies they can undergo a Style Change which grants increased strength and new Deck Commands. There are certain Command Styles that all of them can change into but they have their own unique Styles that only one can perform. Command Styles allow a different method for each of them to fight with either Magic or combo attacking.

Command Styles (LV1)
Upon meeting certain requirements while filling up the Command Gauge (located right above the Command Deck), a character may undergo a Style Change rather than executing a finishing attack. Every style change has certain requirements for activating; an example of executing Diamond Dust would be to fill up the last remaining portion of the Command Gauge with an Ice-based attack.

General
These are available to all three Keyblade warriors.
 * Thunder Bolt: A swift Command Style that unleashes powerful lightning upon attacks. Activated by filling the Command Gauge with Thunder-based commands.
 * Fire Blazer: A ranged and versatile Style that focuses the Keyblade to erupt in flames while attacking. Activated by filling the Command Gauge with Fire-based commands.
 * Diamond Dust: An ice-based Style that seems to specialize in crowd-control and dealing with multiple enemies. Activated by filling the Command Gauge with Ice-based commands.
 * Ice Blast: Another ice-based style that uses an ice cream theme. Randomly activated by filling the Command Gauge with an Ice Cream item.

Terra

 * Fatal Mode: An exclusive powerful fighting style for Terra that utilizes slow, but heavy hits to their maximum. Activated by filling the Command Gauge with physical-based commands.

Aqua

 * Magic Wish: Her own exclusive Command Style; it utilizes the power of light to to hover her Keyblade in midair, swiftly attacking enemies while enhancing her magic capabilities as well. Activated by filling the Command Gauge with a variety of multiple magic-based commands.

Ventus

 * Speed Rave: Ven's personal fighting style that puts a large emphasis on overwhelming enemies with wide-ranged, speed-based combos. Activated by filling the Command Gauge with physical-based commands.

Command Styles (LV2)
While using a Level 1 Command Style, the player can further achieve a second level by filling up any specific Style Gauge. An example of how this would work is if Ventus finished Fire Blazer's Style Gauge with an Aero-spell - the result will be the powerful Cyclone Command Style.

Terra

 * Rock Breaker: After fulfilling certain requirements, his initial Style changes into Rock Breaker. A powerful and long-ranged Style that works best on the ground, it summons three large earth crystals from the ground to damage enemies. Activated by filling the Style Gauge with direct-hit-Keyblade physical commands.
 * Blade Charge: In this Style, the Keyblade resembles a purple sword. A long-ranged style, as its name implies, it allows the user to "charge up" the attacks for additional damage. Activated by filling the Style Gauge with Fire- and Ice-based commands.
 * Dark Impulse: A mode in which Terra summons the power of darkness to attack enemies. A versatile Style that hits enemies with slow, heavy attacks, but also exhibits long-range projectile attacks. Activated by filling the Style Gauge with Dark- and Gravity-based commands.

Aqua

 * Ghost Drive: Aqua's high speed Style; it allows her to attack enemies at high speeds while using after-image illusions and tricky movements to her advantage. Activated by filling the Style Gauge with Thunder and Magnet-based commands.
 * Blade Charge: In this Style, the Keyblade resembles a Light-blue sword. A long-ranged style, as its name implies, it allows the user to "charge up" the attacks for additional damage. Activated by filling the Style Gauge with Fire and Ice-based commands.
 * Air Rider: A style that gives Aqua a great midair advantage, it allows her to ride her keyblade around to attack foes from above at high speed. Activated by filling the Style Gauge with evasive, or Zero Gravity-based commands.

Ventus

 * Cyclone: After meeting certain requirements, Ven's initial style morphs into much more powerful Cyclone style, attacking surrounding enemies with spin attacks. Activated by filling the Style Gauge with Raid, or Aero-based commands.
 * Wing Blade: A widespread mode change that involves attacking enemies from any direction with summoned spinning swords. Bears a resemblance to Riku and Sora's "Session" limit. Activated by filling the Style Gauge with physical, counter, or Magnet-based commands.
 * Air Rider: A style that gives Ven great midair advantage, it allows him to ride his Keyblade around to attack foes from above at high speed. Activated by filling the Style Gauge with evasive, or Zero Gravity-based commands.

Trivia

 * Terra has a mode with the same name of one of Riku's Duel Sleights: Dark Impulse.
 * Diamond Dust is a reference to the same attack used by the Summon Shiva in the Final Fantasy series. It is also the name of Vexen's Limit Break and a Final Mix Keyblade.
 * The mode changes seem to be the precursors to the Drive Forms.