Voiced by: Kenichi Suzumura (Japanese); Tony Oliver (English) Hajiki is the main protagonist of Gad Guard and is a short-tempered and somewhat jaded boy.
A bit of a degenerate and a punk initially, Hajiki skips school, races the cops on his skateboard or moped, and hangs out at all hours with his similarly punkish friends for lack of anything better to do.
However, Katana develops a very strong and almost obsessive attachment to Saiyuri over the course of the story, her disappearance becoming the main motivation for his actions near the end of the series.
Personality-wise, he shows no interest in much of anything but money and rising to the top of the criminal ladder, his grand intention to rule over Night Town.
Aiko earns Katana's slight trust when she rescues Sayuri from a dangerous spot in the middle of one of his battles, who then brings him lunch daily.
Takumi, however, earned Katana's disdain almost to the level of that of Hajiki due to his meddling and loud mouthed sense of justice, and he delights in baiting and teasing him coldly only to prove that he is superior to the short-fused boy.
Katana has a habit of pushing Zero to its limits, as he does with himself, not recognizing damage until it is so severe the Techode kicks out and fails in tough spots, overcome with the strain.
As she came from a good part of town, Arashi has some trouble initially adjusting to life in the ghetto, such as her belongings getting stolen and not having batteries to cope with the power shutting off at midnight.
She is witness to the creation of Lightning, and after seeing Zero (belonging to Katana), Thunderbolt (Takumi), and Messerschmitt (Aiko), she longs for a Gad of her own, something she later finds by accident.
Hayate, named for the Japanese word referring to the winds, is modeled after Arashi's desire to fly, a symbol of her freedom, and thus she never uses it in battle, but only to rescue the others and herself from danger and perhaps to feel that she fits in with the other Techode owners.
Takumi is a short and wealthy boy who lives in Day Town; his most defining attribute in the series is being almost obsessed with justice and the differences between right and wrong.
So because of his abundance of money and free time, using his Techode Thunderbolt, he goes out and attempts to solve crimes and punish evil-doers, because he wants to do something good, as he feels the local police force is very lacking.
Aiko, however, acts much as Sayuri does to Katana and insists to Takumi that they should all be friends, even suffering to handle his temper and bad attitude, only to smile and continue to talk with him.
The adopted daughter of businessman Larry Harmony, the owner of Central Electronics - the biggest electric company in Unit Blue - Aiko is a sweet girl, but very conflicted.
Unlike the others, Aiko lives in Gold Town, the rich district of Unit Blue, and because she has every luxury, she is not spoiled, but she is very idealistic, carrying the belief that, because all five of the kids in Gad Guard were "given" Techodes, they all have something in common and therefore should all be friends.
Being raised the only child in a rich family, where her father is too busy for her and her mother is only on-camera four or five times in 26 episodes, Aiko is very lonely, and it is for this reason that her Techode, Messerschmidt, takes the form that it does.
Aiko found Messa's Gad in a drawer in her father's expensive car garage, where she activated it, only to have it suck up everything inside of it to form her Techode.
Messa is, in form, a titan, huge and imposing with a facial cast that looks like it has a beard, and a big thick body that is meant for protection.
For whatever reason, this child, armed with a pink coat, a bunny plushie and a big smile, refuses to leave, following the not-so-welcoming boy wherever he goes with the claim that she is his "friend".
After having her around and being unable to damage her, no matter how she waddles around after him and pesters him, Katana becomes accustomed to her, and finally grows attached to her, to the point that she comes with him everywhere, even answering his job phone for him to take messages.
Sayuri is possibly the only person or creature Katana has ever truly and completely loved since the day he lost his memory, if only because she is the part of him that remembers, and the proof that he is, at heart, just a lonely little boy.
Originally having hired Hachisuka Express to bring her a Gad, Wanda Woman impersonated her and got Hajiki to give it to her at her apartment while she was not home.
Kyoko is a big woman, and like most single mothers, she has no problem punishing her degenerate son for skipping school and falling asleep in class.
Later in the series, Jacque becomes a big plot key when an old photograph comes into his possession, one that Katana wants badly enough that he rips the roof off of Hajiki's house to get it back from him.
At some point, this gets her in serious trouble when she accidentally swallows a Gad in the shape of a jewel, only to have Jacque punch her in the stomach to make her cough it up...which activates it.
She does, however, use him against her none-too-smart boyfriend in the beginning by having him give a monotone "hey" into the phone while she is talking with him, then telling him she is busy and hanging up on him, to see if Jacque would get jealous.
After being orphaned as a child in a shipwreck, from which he was the only survivor, and losing his memory, Katana wandered aimlessly around Unit Gray until he was found and collected by a man named Radigue.
In fact, he is very distrusting, as his work is competitive, and has his base of operations booby trapped with bombs and other deadly things, all set on trip wires.
He calls his unofficially adopted son a brat and a punk and shoves him around, which shows where Katana got his nasty nature... or maybe Radigue developed it to handle him.
He does very much love the boy, and while Katana never truly says it out loud, he sees the man as a father-figure, even resenting him for treating him like a child and speaking of his quirks to others (such as an eye-twitch he has that signifies his being happy, being that he never smiles).