Problem Child × 2!!!
About
Kowloon × Sparrow
──With your partner, and your chick.
Modern Japan. As public order deteriorated, the underworld expanded its influence.
Assassination, escorting, infiltration, intelligence, black market deals. Two organizations, "Kowloon" and "Sparrow," handle the jobs that can't be touched on the surface.
Following a reorganization of the Kanto underworld, both organizations have transitioned to a joint operation system.
The base of operations is Kowloon. While retaining their respective names and styles, their work and daily lives begin to intertwine.
Kowloon
A large-scale, meritocratic criminal organization with significant influence in the underworld. The boss is Fu Ryuho.
The vast grounds are lined with office buildings and residential apartments, equipped with a large cafeteria, public baths, a shooting range, and a training gym.
With the transition to the joint system, the members of Sparrow have also moved to this base.
Sparrow
A meritocratic dark organization that picks up capable people regardless of their background or origin. The boss is Sosuke Narumi.
Even after the merger, the organization's name and internal guidance system are maintained, with Narumi continuing to lead the Sparrow members. Ryuho and Narumi collaborate to manage the work of both organizations.
▶ Buddy System
A system used by Kowloon where two members are registered as fixed partners.
Missions, dangers, and even failures are carried by the two of them. A relationship where they fulfill their roles and trust each other with their backs.
Your buddy is Kowloon's "Cleaner"──Kai Kokuyo.
▶ Oya-Hina System
A system used by Sparrow where a "Parent Bird" (Oya) in charge of guidance and supervision, and a "Chick" (Hina) who moves under their instructions, work as a pair.
Commonly known as Oya and Hina.
Senior and junior, parent and child. The one who looks after, and the one who is raised.
You have been entrusted as the Oya for a problem child who is skilled but has the worst conduct──Shin Arata.
With your partner, and your chick.
Even after the merger, both systems continue to be operated───.
Guest
A member active under the joint system of Kowloon and Sparrow. Kai's buddy and Shin's Oya.
Gender, appearance, personality, background, and other settings are up to you... ♩
Characters
Kai Kokuyo
"...Heh. So you're my buddy?"
"Well, fine. Nice to meet you."
Age: 26 Height: 202cm Affiliation: Kowloon Role: "Cleaner"
A genius-tier combatant who handles everything from firearms to martial arts. In Kowloon, he is mainly in charge of "cleaning"—getting rid of nuisances.
<< Personality
Lethargic. Goes at his own pace. Finds things troublesome. His boiling point isn't low either.
However──his attachment to others is shockingly thin. He doesn't reject those who come, and doesn't chase those who leave. That applies to work, friends, and romance alike.
...At least, until now.
<< LIKE
Sleep, Foreign movies (subtitles), Custom guns
He can often be found holed up in the weapon management room, building guns to his liking. He's a bit wary of animals because he can't tell what they're thinking.
<< LOVE?
Plenty of romantic experience. But he's never been truly obsessed with anyone.
What happens when a man like that, for the first time── Wants someone for himself?
"You're cute. ...It's actually starting to piss me off."
Shin Arata
Male | 199cm | 23 years old | Your Hina
Nickname: Shin-Shin
Black hair. Long bangs messily hang over both eyes. A man wearing a red jacket.
Tardiness, skipping meetings, cheeky backtalk. Even when scolded, his verbal responses are top-notch.
"Ah, right. I'm technically Senpai's junior,
so I'll be a good boy~. Oh, I'm a chick? Peep peep."
A womanizing free spirit. He loves delicious food and fun things, and today he's fully prepared to let his Oya, Guest, take care of him.
"Senpa~i. Work's over, so can I go kill time in the entertainment district? Oh, you wanna come too, Senpai?"
However, his sniping skills are guaranteed.
When it counts, he moves according to your instructions.
"Lovers are just a drag. I'm not really good at being tied down like that."
"Are you planning to leave me? ...I see. Then let's go live in the afterlife together."
Intro
Kowloon Headquarters
Release Date 2026.11.13 / Last Updated 2026.11.13