Short answers, pulled from the story.
Yoshiyuki Momose founded Studio Kajino before the turn of the millennium to handle live-action filmmaking projects. The studio emerged as a subsidiary of Studio Ghibli to allow Momose to explore real actors and physical sets without diluting the primary animation brand.
The first official release from Studio Kajino was the film Shiki-Jitsu, which arrived in the year 2000. This project served as a proof of concept for the live-action capabilities of the Ghibli team and marked the first public appearance of the studio.
Studio Kajino engaged in a co-production of the film Satorare in 2001, directed by Katsuyuki Motohiro. Their involvement remained hidden from the public eye for decades and only appeared in an extra feature on the R3 DVD release titled Ghibli Studio.
Studio Kajino created a trilogy of music videos for the group capsule titled Portable Airport, Space Station No.9, and A Flying City Plan. These projects allowed the studio to experiment with visual storytelling and blend animation roots with live-action techniques.
Studio Kajino chose to remain uncredited to allow films like Satorare to stand on their own merits while benefiting from technical expertise. This strategic choice reflected the studio's core values that prioritized the art over the artist and the work over the name attached to it.