Absolute Control

"The air in the Oblivion Fortress has been purified, right?" Diego asked, glancing at Hazel with curiosity.

Hazel nodded. "Not just the air, the water and soil have been purified too. Nothing here will get contaminated by the apocalypse."

"There are 888 floors in total, and you've seen how massive it is. It seems to go on forever. Until the outside world is safe again, we can rely on the Fortress