Kaito Wanijima, also known as the "Shinjuku Crocodile" is Agito/Akito/Lind Wanijima's older brother or rather, their biological father and the leader of the Windstorm G-Men, a special S.W.A.T. team that was created specifically for hunting down and arresting Storm Rider teams.
Kaito is a tall middle-aged man with long white hair down to his lower back and lets it roam freely. He usually wears a simple A-shirt and baggy pants with a gun in the side. He's usually seen smoking.
Ten years ago, his appearance was the same, except his hair was shorter and he had some of it tied in the back.
By his own admission, he states he's over 30.
Kaito is very ruthless, apathetic, serious, and a forceful and serious man when it comes to his job. He usually forced Agito/Akito/Lind to do as he was told and didn't care about the people that he hurt. He tends to be cocky and underestimates others. He doesn't seem too ruthless, as he uses rubber bullets when shooting most the time so others don't get killed (though that won't stop him from shooting others regardless). He would always force Akito to do as he's told and would always lock him up in a cage so he wouldn't run away and could use him as a weapon forever, showing a rather possessive side on Kaito's part.
However deep down, Kaito has shown that he's not a man without compassion. There are those that he truly cares for, the first being Gazelle, Agito/Akito/Lind's mother and the woman Kaito loved. In fact, Kaito did everything in his power to keep Gazelle alive so they could be together and refused to abandon her and even cried over her death. He cares for his comrades almost as much, because he has been shown mourning for them after they are killed by Nike. Even Agito has been shown love from Kaito, since the main reason he locked Agito up was because he wanted to protect him, since he didn't want to lose his son like he lost Gazelle. This makes Kaito an "over-protective father" to some.
He is also a chain-smoker, that no matter where Kaito is, he's always seen smoking.
History10 years ago, before the general public knew about ATs, Kaito was the leader of a skateboarding gang called Yellow Rain, which acted in a very similar way to the more criminal AT teams such as the Skull Saders . It was during this time that he met the original Thorn Queen Gazelle, injured on the street without her memories. He enlisted her into the team, which caused them to come under even more scrutiny from the police, due to more and more damage being caused by these "flying shoes", leading to the police using an undercover agent within Yellow Rain, Kakiya (although this was not known to the team or Kaito at the time). Kaito helps Gazelle by teaching her the things about life she did not remember, and by taking care of her. Over time Kaito came to realize that Gazelle was the one person more "free" than him and develops feelings for her, that she returns.
It was while she was living happily with Kaito that Nike eventually tracked down Gazelle due to one of her allies selling her out. It is revealed the she is on the run from the Takeuchi brothers. Nike attempts to kill the man who gave him the information due to his twisted personality, but Gazelle saves him. The two engaged in combat, but just when it seemed that Gazelle had gained the upper hand, she gets overwhelmed by the combined offensive power of both Nike and Sora, who joins the fray. Kaito meanwhile had been entrusted AT armour by Dr. Minami for the purpose of saving Gazelle from this predicament. Once he arrives at the scene of the battle, he uses his armour's weapons to try saving a downed Gazelle from the twins. The two prove too powerful however, and Kaito realized he cannot win the battle. He urges Gazelle to run with him, but she is afraid of putting his life in danger (to which Kaito furiously protests). Before Gazelle can be harmed by the twins during this exchange, the man who sold her out uses his skateboard to knock into the twins in the air. He happily exclaims that he finally got a chance to fly, before being mercilessly slaughtered by the two of them. However, by now Kaito has taken Gazelle and had enough time to run away.
The two flee Japan, intending to running away to Russia. Gazelle keeps telling Kaito that he didn't need to keep running like this, but he refuses to listen to her and wants to get her out of danger as much as possible. He tries leaving a trap for the Takeuchi brothers in the middle of her journey to Russia, but it fails, and the twins ominously rise up to continue their battle. While being stuck on pieces of ice in the freezing ocean, Gazelle realizes that she cannot escape and decides to commit suicide, in an attempt to deny the Takeuchi brothers access to the powers they seek from her. Kaito screams at her to stop, and is devastated by her dying. From her corpse, the Takeuchi brothers retrieve the core of the thorn regalia, and Kaito is eventually saved from the sea in a comatose state by a Russian coast guard ship. He returns to Japan and enrolls in a university, along with most of his old Skateboarding gang. He decides to pursue a career in law enforcement, seeking revenge for the death of Gazelle and deciding to fight against all the damage that ATs could cause, having seen it himself.
Kaito begins to then live with a police officer who in the past would hound him for his crimes; Kakiya's father. One night, a child appears at Kaito's doorstep; one who bears an uncanny resemblance to Gazelle. The boy carried a note from Dr. Minami, and it is explained that he was able to retrieve Gazelle's body from the sea, and with the technology available to him, he was able to revive the child Gazelle carried (who had to be matured from being months old to being a few years old in order to stabilize him.) Agito/Akito/Lind Wanijima is revealed to be the child of Gazelle and Kaito - and he is entrusted to Kaito. Kaito embraces his child in pure happiness, feeling his heart can finally move forward again. He decides to protect him at all costs.
Kaito Wanijima is introduced as Agito/Akito/Lind Wanijima's older brother and the leader of the Windstorm G-Men, a special SWAT team that was created specifically for hunting down and arresting Storm Rider teams. They use special ATs that are hidden in their pant legs and form around their footwear. Kaito views his brother purely as a tool, constantly keeping him in a cage and punishing him with a bullwhip and a gun that fires rubber bullets.
In the days of the original Sleeping Forest, his interactions with Gem King Kilik inspired the latter to fight against Takeuchi Sora and reinvent Sleeping Forest to protect the A-T world from the influence of the Sky Regalia.
He is later shown flying to Genesis' aircraft carrier, along with Udou Akira. When he arrives, he uses a rocket launcher to blow a hole in the side of the ship, then enters the carrier to back up Agito in his battle with Shalott and Arthur. While battling against Shalott and Arthur, Shalott blocks his bullets with a Rumble Wall and destroys his gun before mocking him. Shalott questions his abilities in regard to being the leader of the G-Men before deducing that Kaito's real name might be Gazelle. Kaito, however, refutes this claim, and then proceeds to pronounce that his little brother, specifically the personality of Lind, is actually the true Gazelle - the original Thorn Queen.
Kaito's past is then revealed, and it is explained that Lind carries the battle style and memories of Gazelle. Agito and Akito realize that Kaito kept them in a cage to make sure they stayed protected, and did not want them to join Kogarasumaru because he was worried of the dangers they could face as part of that team. Lind then uses his power to seriously injure both of his enemies, freeing Kaito. Kaito however then gets impaled (in a non lethal way) by Arthur, who has survived. Arthur explains that Kaito will die if Lind does not win the fight quickly. After an exhausting continuation, Lind succeeds, and Agito takes tends to Kaito's wound. Agito then says (to Kaito's
complaint of how his arm may no longer work) that if Kaito ever needs a drink, Agito will hold up the cup for him. Kaito guesses that Agito must have heard about the past, but hits him on the head for his unsually sweet wo
rds, implying he needs no such tenderness. The father and son duo are then confronted by what appear to be the spirits of Arthur and Shalott, who say that their final wish is for the Takeuchi twins to be defeated. Kaito and Agito agree to this. However, before they can move for Lind, Kaito gets a call from Akira telling him that the s
hip they are in is in danger due to the releasing of a gas valve, and Kaito tells Agito they must exit.
At the end of the manga, Kaito is given hope that he could see Gazelle again by using Dr. Minami's research, but immediately fell into depression when he heard that she would be a baby instead.