Gai is a tall man who is a head taller than Shu. He has long blonde hair and light blue eyes. His typical attire consists on the Funeral Parlor's uniform.

After being resurrected, Gai now sports clothing very similar to the Anti-body uniform. He has also gone albino, shown by the loss of pigment in his hair and eyes now red. In addition, Gai also has crystals near his right eye.

Gai was first found by Shuichiro Keido, who used him and many other boys in his experiments to create an Adam for Mana. The experiments involved injecting artificially-enhanced samples of the Apocalypse Virus on several boys, of which Gai was among. Out of all test subjects, Gai was the one who better responded to the virus. At one point in fear he ran away for the facility, in fell in the sea and was found by Mana and Shu. He was nursed back to health by them, and lived with them. He fell in love with Mana and became best friends with Shu. Gai soon realized that Mana was infected by the Apocalypse virus and attempted to tell Shu of Mana's insanity. But Mana found him first and gave him a gun. By asking him to shoot the star on top of a Christmas tree, the bullet rebounded back at him. He later protected Shu, when Lost Christmas occurred. He later left to get stronger, at which Shibungi states that he met Gai as a child soldier in Africa

He has a lot of charisma and is Shu's rival. He guides Shu who has the "Power Of Kings" and aims for a successful revolution. He also appears to be able to 'see' the Void that is inside of a person and is highly intelligent. He is a great strategist, able to create very complex plans that are able to predict people actions. He is manipulative as shown in Episode 7, to get the Kuhouin group's support he manipulated GHQ to attack the ship, they were on. Then manipulated both Shu and Arisa to stop the missiles to show the Undertakers abilities. In Episode 6, he reveals his arrogant, bold and cold personality is a front for the Undertakers. He takes the members deaths very seriously and thinks very little of himself, like Shu. But due to his manipulative nature, it is hard to question if it was the truth or a ploy to get Shu to join the Undertakers. Gai has stated his reason to fight is to find a woman (later revealed to be Mana) and take her in his arms. After his resurrection he is a cold and ruthless man who shows no remorse against people he associated with in the past as he had no qualms severing Shu's right arm. He reveals that his role as leader of of the Funeral Parlour was just an act and their he of thought of them as his pawns as a King has no friends. However in the Final Episode he reveals that he played the role of a villain to stop Mana from resurrecting herself and Shu will be the one to stop them.

Gai is seen showing up to fight the thugs who had attacked Shu and eventually scares them away. He comes up to Shu and asked him if he just abandoned Inori but before he could continue a huge explosion occurs. Someone then shouts out saying that the GHQ were attacking and they all head to the front lines. Gai asks Tsugumi how Ayase and the others were doing and she tells him that an enemy was coming at them from the left. After Ayase destroys it, Gai yells at Shu telling him to protect the Void Genome and runs off. Gai is later seen in shock at Shu's newly awakened power. After the battle, Gai orders Shu to take Inori and bring her to him in fifteen seconds. They soon arrive there and before Shu could speak, Gai gets a call from Ayase. She apologizes to him for failing her mission but blushes when Gai tells her he's glad she was alive. He returns his attention to Inori who just woke up and tells her he was disappointed in her, saying the Void Genome was for his use. He goes on to explain what Voids are and tells Shu that he's not allowed to stand and watch by the sidelines. Before Shu can protest, Gai grabs him by his shirt and tells him that he can either be selected out
Guilty Crown - 02
of this world or adapt to it and change. He receives a call from Arugo, who tells him that the Anti Bodies have captured some people who were taking shelter in a building. Gai meets with the rest of Undertaker and forms a plan to rescue them. After the plan starts, he reveals his identity to the GHQ before Guin starts a countdown and says that if they don't surrender he would die. However, Shu uses the Kaleidescope to reflect the lazers back onto Guin, killing him and some other GHQ members in the process. Later, Gai offers Shu to come and work for the Undertaker but is turned down. Sometime later, Gai reveals Undertaker to the rest of the world and states his goals. He later informs Shu of someone who goes by the codename Sugar that witnessed the previous events that happened. He states that the only way to make the person forget is to extract their Void. Gai disguises himself as Shu's lawyer when he got arrested by the GHQ, in order to save Kido. When the plan went sour, Gai changes the plan and it ends up prevailing. After the battle Gai finally persuades Shu to join the Undertaker and they set off. Gai reveals Shu to the Undertaker and orders Ayase to train him if she valued her life. He is later seen walking into a room with Inori and it is revealed that he has to take her blood two
Gai taking Inori's blood
to three times each month, for an unknown reason. After, Gai sets the first part of his plan into action to take the Leukocyte, but this backfires when it attacks the area they were in. It kills all of Gai's teamates and Kyo so Gai decides to change the plan. While taking Inori's blood, Gai questions himself on why he was doing all of this, saying it took all he had just to keep up the 'leader' act. He is over-heard by Shu, and they get involved in a fist fight. Shu punches Gai to the face, knocking his chain off. He tries to reach for it but can't because of his injury. Shu picks it up for him and tells him that he'll help and Gai calls him an idiot. They carry out the plan to destroy the Leukocyte by using Kido's Void, before they are interrupted by Daryl who wants revenge because Gai humiliated him. Gai defeats him quite easily even though Daryl was in his Endlave, which Shu is amazed about. Gai is revealed to have known that Shu had the 'pen' that Segai gave him, and uses it to let the Leukocyte target him. However, Shu shows up with a new Void which was given to him by the girl that resembles Inori but Gai refuses to tell Shu who the owner of the Void was. They succeed and Shu tells Gai that they were both accomplices and Shu helps Gai up. After some days Shibungi informs Gai that they are running out of supplies,although they had still some savings they have no route to transport new supplies, Gai apparently knows someone who will help them.The next night Gai and Shu disguise themselves as Butler and attend a party on cruise ship to make a
Gai likes to force himself on others
deal with the Head of the Kuhouin group (also known as Arisa's grandfather). Accidently Shu runs into Arisa who tries run away from her he tells Gai to take care of the rest Gai stops Arisa to chase after Shu,he tells her that she is like his armadillo pet that he had when he was young, which makes Arisa furious she tries to slap Gai but he stops her by holding her hand. After Gai makes his proposal to Arisa's grandfather,Shu tells Gai that Tsugumi informed him about a attack on the ship from the anti-bodies,b asks him what they should do in order to save the passengers Gai tells him to meet him at the upper deck.Gai takes Arisa there and tells that he is about to cast a spell on her,she closes her eyes,when she opens them Shu draws out her void and they together successful defend the ship.Gai mentions to her that, she is actually very shy despite the tough image she gives out.
Gai says goodbye and thank you to shu
Gai goes to stop Mana from coming back to life and from Lost Christmas to happen again, and Shu gets his memories back. He finds out that Gai was his bestfriend when they were young.

    After helping Shu rescue Inori, Gai goes to free Mana's soul from the pod containing it. However, the crystals protecting the pod stab him. Close to death and and pinned to Mana's pod, Gai requests Shu to stab him through the heart at the same time, in order to break the pod free Mana's soul. He dies embracing Mana, finally reunited with his lost love. A few weeks after the breakout, Shu and what remains of the Funeral Parlor still grieve for Gai.

In Episode 22

he uses Mana's void to kill Shu for hurting her feelings once again only to let Shu use Inori's void from the flower that contained her spirit and defeated Gai. Afterwards their battle, Shu started to hallucinate and sees Gai standing in the middle of the utopia of Da'at (memories inside the crystals), Gai tells him about the role of natural selection amd evolution that Da'at can simply reanimate Mana even if she dies, she will just come back; never free from the Apocalypse Virus and the only way to only stop it is to fulfill her role. Gai then takes Shu to the church where the advent of the Lost Christmas happened but this time, Gai hugs Mana and they crystallized together, thus freeing Mana from her role and fulfilling Gai's dream to take Mana in his arms. Gai then tells Shu to save Inori as he breaks down along with Mana.
Abilities

As the leader of the Funeral Parlor, Gai is a highly intelligent individual and a skilled tactician, as most of the attacks made by the Undertakers are made under his command. One example is when he and Shu crashed the Kuhouin Group's cruise ship party to rally influential supporters against the GHQ forces; Gai had previously tipped off the GHQ to have them launch an attack while having Shu use Arisa's Void to successfully stop the attack, thus making a demonstration of the Funeral Parlor's power and gaining the Kuhouin Group's support.

Due to perhaps him being infected by the Apocalypse Virus, Gai had the ability to perceive other individuals Voids, using this skill to great effect in the Funeral Parlor's missions by directing Shu on the most useful Voids to use to deal with each situation.
Physical skills

While initially not possessing any supernatural abilities like the Void Genome, Gai possess incredible physical abilities. In his younger age, he was able to survive a brutal attack by a pack of dogs and falling from a large cliff into the ocean. He was also used as a child soldier in an African battlefield, where he was meant to kill Shinbugi, where the latter saw a natural talent on him. He possess great physical strength, speed and reflexes and is a skilled hand-to-hand fighter, to the point where he was able to outfight several GHQ and Anti-Body soldiers single-handedly on multiple occasions.

He also has training in firearms where he's shown to be a skilled marksman, typically wielding a pistol to threaten or kill enemy soldiers. His physical prowess and marksmanship appear as inhuman on some occasions; while trying to destroy the Leukocyte system, Gai was able to single-handedly hold off, out-maneuver and destroy an Endlave piloted by Daryl, a highly-skilled pilot in his own right, by moving to it's head and shooting it in a key point on the head. After his resurrection, he was able to wield Inori's large Void with one hand to slice off Shu's arm, before he or anyone else could react to what happened.
Void Genome


With this new power he can also use his own Void's power without drawing it out allowing him to draw out several Voids at the same time without making eye contact or touching a person. While his use of Void Genome is mostly the same as Shu or Yuu, an individual still collapses from having his Void removed possibly implying Gai hasn't fully mastered his powers yet.

Like Shu and Yuu, he has also shown the ability to combine Voids to create more powerful ones, which he uses to extremely deadly results, such as creating a missile that could not only destroy a stealth aircraft but also produce energy shields strong enough to block a flurry of bombs dropped by it or a large bow and arrow with enough power to nearly destroy an entire U.N fleet with one shot.