Shakuzawa Building

The Shakuzawa Building (酌沢ビル Shakuzawa Biru), located in Shinjuku, is home to an unauthorized daycare center for children of women who work in nightclubs and children orphaned after their parents were killed due to mafia involvement.

The Incident
When ambulance sirens sound in the distance during the standoff between Clarissa Kuraki and the Corpse God, Takumi Kuruya informs Clarissa the Shakuzawa Building is on fire and—via his on-site drone—sends live footage of the scene to her tablet.

Once the Corpse God learns of the unauthorized daycare, he rushes to the scene by way of Takumi's guidance; detecting the life-forces of children within the building, he summons a gigantic skeletal hand via necromancy which carries him up to the window of a room where four children and their adult caretaker are curled prone on the floor. Watching over them are the spirits of the children's parents, who assist by lifting their children up and through the windows to the waiting skeletal hands outside. The hands safely deliver all five people—unconscious but alive—to the ground and disappears, letting emergency personnel take over.

Neither the large skeletal hands nor the spirits escape at least some bystanders' attention, and photographs and videos of both the hands and the skeletal figures seen through the smoky windows are swiftly uploaded to social media websites.

Aftermath
The Shakuzawa incident immediately captures the attention of Comps-3, a group dedicated to investigating Shinjuku's troublemakers. While the fire is assumed to be the work of Fire-breathing Bug, the skeletal figures are a new phenomenon which may herald the arrival of a new troublemaker to Shinjuku.

As part of his investigations into the Shakuzawa fire and the human knots incident, Comps-3 manager Tsubaki Iwanome brings up both to Clarissa at her bar—since he knows she is involved with some of Shinjuku's troublemakers to some degree.

Over a week later, Iwanome—with Kōzaburō Arase—shows photographs of the skeletal figures seen at Shakuzawa to Tena Sorimura, a troublemaker bound by a straitjacket. Iwanome talks about the Fire-breathing Bug's possible modus operandi for a while; during the discussion, Sorimura states that the Shakuzawa fire was in fact the work of Know, a mere impostor of the real Fire-breathing Bug. Sorimura himself is far more interested in the skeletal figures than he is Know, as someone in pursuit of real magic, and he proceeds to break out of prison so that he may better investigate the skeletal phenomena.

Later after the Shinoyama Mansion Fire, Takumi Kuruya hacked into the police database to learn that the suspect of the fire was identified to be Know who was impersonating Fire-breathing Bug, who took offense to this by incinerating the arsonist whilst he was in police custody.