Hero's Cave

Hero's Cave (勇者の洞窟) is the nickname given to a dentist clinic located in the School District 7, where a pediatric dentist works.

Principles
The clinic contains all the necessary tools and equipment to operate. Standard rooms such as the waiting room are present.

As for the dentist, he is relatively blunt when it comes down to talking to a child about their health, and is completely professional, and has two to three assistants with him during an operation. He is referred to as the most skilled and frightening dentist in School District 7 by the neighborhood children.

Ichihanaran Festival Arc
The establishment is first shown when Fremea Seivelun is getting a surgery for her tooth after continuously drinking too much hot chocolate every night before going to bed despite Hamazura Shiage and Takitsubo Rikou's warnings.

Saiai later accompanies a powerless Kuroyoru Umidori into the establishment after Shiage noticed that she somehow stopped chewing with her back teeth. Due to Shiage sticking a gum into the ports of her cybernetic arm, she is rendered powerless as she cannot create nitrogen spears. As such, Umidori is under the mercy of Saiai, who forces into the clinic.