According to Koku Hanabata, Deika City is a "Liberated District" where 90% of the inhabitants, including the heroes, are soldiers for liberation. Upon first glance, Spinner calls the city the perfect size, not too big or small. 
Deika is a city in the mountains, so its entrance and exit routes are limited and can easily be manipulated by the army. It's described as a city surrounded by nature, the perfect place for the liberation army to hide. 
- Deika contains the kanji dei (泥? lit. "mud") and ka (花? lit. "flower") put together means "muddy flower".
- If the kanji is reversed (花泥) they start the saying "it's no crime to steal flowers".