Dr. Crombel's personal soldiers. They are often seen throughout the series battling the members of the Raizel Knights.
A modified human who is introduced as a member of the 12th Elder's faction as Dr. Aris' assistant. He reveals himself to be a mole for Crombel during Cerberus' war against the Raizel Knights, and provides his boss with many research samples.
- Badass in a Nice Suit: Always seen wearing a nice suit. Even in combat.
- Battle Butler: To Dr. Arith.
- Dark-Skinned Blond: dark-skin with blonde hair.
- Faux Affably Evil: Puts on a normal person act when he's not acting evil.
- Four Eyes, Zero Soul: Just like his real boss.
- Frickin' Laser Beams: From his fingers. Apparently with Power Nullifier.
- Love at First Sight: To Seira.
- The Mole: He is introduced working for the 12th Elder when he's actually been working for Dr. Crombel.
Crombel's personal modified human bodyguard early in the story. Mary was considered the squad's weakest member, but still proved to be a worthy enemy for Rai and company early on.
- Absolute Cleavage: Her shirt shots off her breasts.
- Curb-Stomp Battle: On both the giving and receiving ends.
- Curtains Match the Window: Blue-hair with blue-eyes.
- Dark Action Girl: She is the first female combatant to appear in the series. She is very stoic and shows no mercy towards enemies to the Union.
- Ms. Fanservice: A group of men on the street comment on her good looks.
- Red Oni, Blue Oni: Guess which one?
- Spell My Name with an "S": Her name is also often romanized as "Marie".
- Worf Effect: She's built up to be a major threat early on, but ends up having a surprisingly early death.
Mary's modified human partner. Having previously killed a large sum of Union members, Jake was scouted out by Crombel, and Mary, to see if he was skilled enough to become a true member of the Assassination Squad.
- Jerkass: To anyone he deems lesser than himself (which is a lot of people).
- One-Winged Angel: Towards the end of his life, he modifies himself further allowing him to achieve a stronger combat form.
- Sadist: He likes to kill people just to display his strength. Even after Marie told him not to kill Shinwoo & co. until the fourth kid (Rai) showed up, he still tried to make them suffer.
A modified human of the squad who works as an undercover agent. After finding his remains, Crombel tasks him to take the disguise of M-24 in order to infiltrate Frankenstein's research labs to acquire needed data for his research.
A member of the squad introduced working for the 10th Elder, Rostere. He joins up with Yuri to catch the Raizel Knights trying to plant evidence that would incriminate Crombel's work to the rest of the Union.
A member of the squad specializing in poison usage. Kalvin stands alongside Yuri and Mark when they are attempting to steal the last of Frankenstein's research.