About four and a half years before the start of the series a gate to another world opened and Neighbors appeared in the city and started attacking. A mysterious group named Border appeared and repelled the neighbors. In 2 days East Mikado was destroyed over 1200 people died and more than 400 people are still missing. Afterward, Border built their base in the city to protect it from Neighbors.
|Third Mikado City Junior High School (三門市立第三中学校 Mikado-shi Daisan Chūgakkō?)||It is a school located in Mikado City which Osamu, Yūma and Chika attend.|
|Yumite District Station (弓手町駅 Yumitemachi-eki?)||It is a train station located in Mikado City which has been closed and relocated at New Yumite District Station due to its close proximity to the Danger Zone.|
|Kanoya (鹿のや?)||A well-known traditional sweet shop that once located in East Mikado but relocated to Umebayashi after the shop was destroyed during the First Large-Scale Invasion.|
|Jujuen (寿寿苑?)||A BBQ restaurant located near the Danger Zone which many Border agents are regular customers.|