"You know, we get air from outside through the filtering system in the outer walls."
"Yes, I realized that."
"And you realize that the weakest point of this city is the air filter."
What Kento said was very true indeed. The city that looks very beautiful from above has a flaw in its construction. To Luke he looked at this city as if the middle class people were protecting people of higher economic strata and status. Just look in the middle of this city there is a magnificent castle surrounded by four small castles. The majestic castle in the middle was the ruby castle which was the place of the king who hadn't even appeared for 10 years. I do not know what the so-called king did. In fact, in the incident 5 years ago he did not appear as if the king had abandoned his people.