- Ax-Crazy: Simply put, what his little idea of morality is lacking sanity.
- Child Soldier: He is still in his early teens when he completed his training and currently in the the series, yet he has natural talent to drive massive mecha.
- Dark and Troubled Past: Whatever it is, it results with Takechi adopted him and other kids. The military training take its toll to him and then mass media found them.... The novels also implied that he did something that somehow got his actual older sister killed accidentally.
- Far East Asian Terrorists: The only member of A21 who can pilot the Behemoth.
As a young girl without any family, Seina found sanctuary in the A21 juvenile assistance group under the leadership of ex-mercenary Takechi Seiji. The leader was the only father she ever knew and her dedication to the group was unmatched by any other for this simple fact. When the A21 was discovered by the mass media it was assumed to be a terrorist training camp, affecting Seina greatly. Once the great leader Takechi fell to suicide, Seina took it on her own shoulders to continue the name of the group.
- Arc Villain: Of the Behemoth arc. Takuma is most featured but she is the running the show and the organization's leader.
- Dark and Troubled Past: Whatever it is, it results with Takechi adopted her and other kids. Then mass media found them....
- Far East Asian Terrorists: Ironically turns A21 into a terrorist group after the media accused them of being in a terrorist camp.
- Hoist by Her Own Petard: Dies when Takuma takes off in the Behemoth, the mech she forced him into flying. The roof falls on her as he makes his escape.
- Manipulative Bastard: At least towards Takuma, pretending to be his sister in order to get him to fly the Behemoth. Her talk with Kalinin suggests that she's ashamed by it, but has no choice but to carry the masquerade in order to wreck havoc in Tokyo.
- Noodle Incident: Whatever happened with the camera crew investigating A21, and the 'atrocity' that most of the delinquents were involved in before Takechi found them.
- Parental Substitute: To Takuma and their "younger siblings" and she is an unpleasant one at that.
- Save the Villain: Kalinin risks his life to go back and save her, but she tries to shoot him instead, only to be injured when a beam falls on her. She carries Kalinin to safety, then dies.
- The Spartan Way: Takechi's training camp. It gives them pride and self-confidence, but doesn't prepare them for coping with the outside world when it intrudes. A21 therefore becomes the terrorist group they were accused of being.
- You Remind Me of X: She spares Kalinin's life because he reminds her of her own Parental Substitute.
A bad guy from the Surplus manga. A promising Mithril SRT recruit who washed out in his training in Belize, he's the Arc Villain responsible for stirring up up tensions in the Taiwan Strait.
The military dictator of Balic, he's the main target of Mithril's WPF op in The Second Raid. He uses Amalgam-modified Patriots to take out Teiwaz 12.
- Asshole Victim: Maress gets killed by Gates after refusing to pay up, seeing that their weaponry didn't deter Mithril from saving the refugees.
- Canon Foreigner: Gatou conceptualized him for The Second Raid.
- Small Role, Big Impact: His use of the modified Patriots on Mithril's choppers alerted the leadership that Amalgam was supplying him with them alongside the Mistral-I Is.
- Would Hit a Girl/Would Hurt a Child: He doesn't care if the minorities he wipes out are all women and children.
Quang Van Dao
The brutish arena combatant of Namsac, who pilots the customized Mistral-II called "Ogre". He's not quite the friendliest person around town, but has a little bit of more hate in his heart reserved for the Crossbow team and any who ally with them.
- Ax-Crazy: He's rather brutal in general, but can reach unhinged limits when his pride is wounded.
- Combat Pragmatist: He resorts to murdering his opponents more than one time, and of course being in a corrupt and undeveloped town that is merely recovering from a war helps him get away with almost anything.
- Disproportionate Retribution: Nami threatens him with a revolver (non-functional at that) at one point. His revenge? Literally stabbing her AS pilot in the back while he was drunk.
- Good Scars, Evil Scars: He has two huge scars, and he is a jerkass.
- The Brute: He's quite tall and muscular, and his AS isn't less scary...but Sousuke on the other hand defeats him in the Arena without breaking a sweat.
- Would Hit a Girl: A vicious piece of work he is. He is not above going after Nami after the match and smacking her with his fists repeatedly while taunting her for his friend's death.
The head of the Royal Thai Police's Namsac HQ, he's very corrupt and leads a bunch of them to maintain the town's Wretched Hive. He also works on behalf of Amalgam after he learns of Sousuke's Mithril affiliations.
Killy B. Sailor
Commander of the USS Pasadena and general pain in the ass to everyone around him. While not actively malicious, his one-sided rivalry with the mysterious Toy Box submarine (i.e. the Tuatha de Danann) and apparent assumption that he's the protagonist of some real-life action movie has made him a regular thorn in Mithril's side.
- Affectionate Parody: Of 80s and early 90s action movie heroes.
- Awesome McCoolname: Which probably doesn't help with his delusions of grandeur.
- Celebrity Resemblance: He's noted to look a whole lot like Arnold Schwarzenegger
- Eagleland: Is 100% 'MURICAN and, in the opinion of his Japanese-American XO, absolutely insufferable about it.
- Everyone Went to School Together: It turns out he served under Tessa's father and had been rescued by Mardukas in the past.
- Foot-Dragging Divorcee: His wife, Eliza, is eager to call it quits on their marriage and move on, having already found someone much more present and bearable. Sailor was hoping that the Pacific Chrysalis cruise could salvage his marriage, but his wife already walked out on him before the day they'd set sail.
- Friendly Enemy: He oddly winds up striking something of an Intergenerational Friendship with Tessa after "rescuing" her on the Pacific Chrysalis, entirely unaware that she's actually the leader of the "terrorists" he's trying to thwart and the captain of the so-called Toy Box he's declared to be his sworn enemy.
- Heroic Wannabe: Mithril even nicknames him "Wannabe John McClane".
- Ineffectual Sympathetic Villain: Tessa even relates enough to discuss her boy problems with him.
- Sitcom Arch-Nemesis: To Mithril.
- The Neidermeyer: As Lt. Marcy Takenaka can attest to.
- Unknown Rival: So unknown that he doesn't even realize who he's one-sided rivals with.
- Unwitting Instigator of Doom: Amalgam is perfectly happy to capitalize on his ignorance to their own advantage.
- Wrong Genre Savvy: Sailor does not appear to realize that he's a minor character in a mecha anime and not the protagonist of a Schwarzenegger action flick. This causes huge problems on the Pacific Chrysalis, wherein he decides he's basically living a real-life version Die Hard and throws what should have been a simple mission for Mithril completely off the rails.