Ventus

Ventus (also known as Ven) is a main protagonist in Kingdom Hearts Birth by Sleep. From the view of the story, it is revealed that he is one of the Keyblade Wielders before Sora and has a strong bond to him. Ventus, along with Terra and Aqua, fights against Master Xehanort and Vanitas. He is the youngest of the three Keyblade Warriors when it comes to age.

While his name Ventus means "Wind" in Latin, Sora's name in Japanese means "Sky". The connection between the two is explained at the end of his story mode.

Kingdom Hearts Birth by Sleep
Ventus is the youngest of Master Eraqus's three apprentices. The game opens up with a clip from his past, revealing a connection to Master Xehanort. In this flashback, Ventus has an Awakening and finds that his Station of Awakening is broken off. He hears a voice (Sora's voice), and he connects with the voice's heart to fix his Station.

Xehanort took Ven to Master Eraqus to learn from him how to become a Keyblade Master. Terra and Aqua met Ven with open arms. However, when Terra asked Ventus about who he was, where he was from, among other things he panicked, eventually falling unconscious. Eraqus revealed that this was because Ven had lost his memories. Afterwards he remained asleep for some time, although he did awaken eventually. It was then that his heart began to heal and he started to form strong bonds of friendship with Terra and Aqua. One flashback scene even shows Terra and Aqua trying to reassure Ven after he lost a training match. Terra even went so far as to give Ven his wooden training Keyblade, which he carries with him throughout the game until he reaches Neverland.

Years later, following the Master Qualification Exam, he once again earns the interest of Master Xehanort and his apprentice Vanitas. After dark hints regarding Terra left by Vanitas, Ven attempts to follow Terra and embarks on a journey of his own in order to save his friend.

Along the way, it is revealed that Ventus was once the apprentice of Master Xehanort and that Vanitas is actually a being created from the darkness in Ventus's heart. During their final battle at the Keyblade Graveyard, Vanitas summons many Unversed to hold Ventus down as he forcefully integrates into him. While Aqua and King Mickey battle the possessed Ventus, Vanitas and Ventus were transported to the Awakening, engaging in a metaphysical battle that resulted in Vanitas fading out of existence. However, this also results in Ventus losing his heart as Aqua later placed his body within the newly created Chamber of Waking within Castle Oblivion. Eventually, Ventus' heart found its way to a young Sora, in his own Awakening, and his heart passed on into Sora's body. Ventus is soras long lost older brother, at the the time sora was only  4 years old.

Kingdom Hearts 358/2 Days
While Ventus does not make a physical appearance in the game, Xemnas and Xigbar see Xion as Ventus. Xigbar reveals that his complete being Braig has met the real Ventus.

Kingdom Hearts II
In The World That Never Was, Sora encounters Xigbar, who mentions "other Keyblade bearers", referring to Terra, Aqua, and Ventus.

Abilities
Ventus is the fastest of the trio, using swift combo attacks with quick movements. Unlike most Keyblade wielders, Ventus wields his Keyblade in a reverse grip. Aside from his impressive speed, Ventus also utilizes a variety of magic, including new and unique spells such as the Zero Gravity. He also seems to have access to some of Sora's very own techniques, such as the Strike Raid. His known Mode Changes are:
 * Speed Rave: Ventus's personal fighting style that puts a large emphasis on overwhelming enemies with wide-ranged, speed-based combos.
 * Cyclone: After meeting certain requirements, Speed Rave morphs into much more powerful Cyclone style, attacking surrounding enemies with spin attacks.
 * Wing Blade: A widespread mode change that involves attacking enemies from any direction with summoned spinning swords. Bears a resemblance to Riku's "Session" limit. Also in this mode, Ventus wields the spinning swords of light in a dual-wielding style.
 * 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.
 * Thunder Bolt: A swift mode change that unleashes powerful lightning upon attacks.
 * Fire Blazer: A ranged and versatile mode change that focuses the Keyblade to erupt flames while attacking.

Additional abilities include:
 * Dimension Link: A mode that allows Ventus to summon characters from other worlds to aid him in battles.
 * Shoot Lock:
 * Photon Charge: Rush to locked on enemies for multiple hits. If the lock on number reaches MAX, a pillar of light raises for a Finish attack (The information for how to input it isn’t written, but according to last year’s trailer, you have to hit once at the correct time.). “Lock on to all enemies in the area.” “A straight attack with the speed of light!”
 * Pulse Bomb: Ventus holds his keyblade backhanded and sends out energy from the light of the Keyblade, causing many small explosions.

Personality
As mentioned earlier, Ven is the youngest of the three Keyblade warriors. Personality-wise, he has many similarities with Sora; he's cheerful, curious, and gets excited at anything new or interesting. He also makes new friends easily in different worlds and really cares about his best friends Terra and Aqua, viewing Terra as an older brother. Ventus is very much unable to cope with Terra turning and subsiding to the darkness in his heart.

Appearance
Ventus bears an uncanny resemblance to Roxas, bearing identical facial features. Further highlighting this resemblance is Ventus's outfit, which is strikingly similar to Roxas's own Twilight Town clothes. He wears a jacket that resembles a fusion of Roxas's (white on the right side) and Sora's in Kingdom Hearts II (black on the left side). The collar of the jacket is red and pleated, again, similar to the collar on Roxas's own jacket. Underneath this, he wears what appears to be a grey vest with a single button and several white, angular patterns on it. He wears a third layer under this, in the form of a plain, high-necked, black shirt. He also has a chunk of dull green and grey armor on his midsection that appears to be under his vest, and another piece of armor on his left shoulder. Master Eraqus wears a similar piece of armor, though more blue-green, and more obvious.

Ventus's pants are also similar to the pants Roxas wore, though Ven's balloon outward slightly before closing up about halfway down his legs, similar to caprice pants. These pants are colored in shades of grey, black, and white. He also wears an ornate, dull green and grey piece of armor on his upper-left arm, along with a black and white checkered wristband that is, once again, strikingly similar to Roxas's, but with white edges as opposed to Roxas's black-edged wristband. Like Aqua, he wears two criss-crossing straps on his chest, on which he wears a silver badge vaguely resembling the Heartless emblem or the Nobody emblem turned upside down. His boots are rather odd when compared to Aqua's and Terra's, as they resemble an armored version of normal street shoes in shades of dull green and grey.

When touching the piece of armor on his shoulder, Ventus becomes full clad in armor. In "Birth by sleep", Ventus's suit of armor shares the coloration of the pieces he normally wears, predominantly sporting shades of green and gold. In this suit, Ventus adds a yellow cape to his outfit that is discolored, almost appearing rusted. The armor on his knee is gold and bears a sharp, upward-pointing hook on the outer side of each one. Ven's helmet has a notably different design from Aqua and Terra's, appearing more squashed and flat at the top. His helmet also has two prongs on either side of his head which point backwards and angle diagonally upward. Strangely, Ven's boots are colored completely gold in this outfit, as opposed to the multi-colored ones he normally wears. In Kingdom Hearts Birth By Sleep, Ventus's armor is altered. He loses his cape, his boots change to more closely resemble those in his unarmored state, and the coloration changes much more than Terra or Aqua's. Ven's armor loses the greens entirely, now sporting steel blue, gold, and black armor, with several red lines decorating it.

At one point in the game, Ventus was possesed by Vanitas and ended up taking on his appearance, except for his head. His eyes were changed to the color of Vanitas's eyes.

Trivia

 * The Japanese Birth by Sleep website's startup screen refers to Ventus as the "Swift Wind Returning to Bonds" (絆巡る疾風).
 * The badge on Ventus's chest slightly resembles the symbol of the Nobodies turned upside down. The same badge is on Aqua's chest, Master Eraqus's belt and Terra's belt (except Terra's is yellow).
 * In the opening of Kingdom Hearts Birth by Sleep, Ventus is shown falling the same way Sora does at the Kingdom Hearts opening movie and the same way Roxas does at the end of Kingdom Hearts II opening movie, but with Ventus, the Kingdom Key and Soul Eater are floating as he falls.
 * In his final battle against Vanitas in his Awakening, Ventus says the equivalent to Sora's "My friends are my power" line word-for-word, adding more to the Ventus/Sora connection.
 * Ventus is shown to stand in the same stance that Sora often does, with his hands behind his head. Several of his attacks also resemble both Roxas's attacks during his boss battle in Kingdom Hearts II Final Mix and Sora and Riku's Limit Eternal Session Kingdom Hearts II.
 * Ventus is one of only four characters in the series to call King Mickey by his name only. Others include Yen Sid, Aqua, and Riku.