The massive ship features five tiers, each catering to different social classes. Tiers 1 and 2 house the wealthiest, including the Kakin royal family and Mafia leaders, while Tiers 3 to 5 accommodate the general population. Crime rates are high in the lower tiers, and public order varies. Tier 5, the lowest, contains 12 submerged decks near the propeller and relies on the Cha-R Family for maintaining order due to limited security.

Tier 3 is in the middle portion of the Black Whale's hull. A thick bulkhead separates it from the upper tiers, which can only be opened in emergencies from the second-tier side. It is arguably one of the least secured areas on the ship, lacking the large number of soldiers found in the upper tiers and the Mafia's interest in maintaining order, especially since Morena, the boss of the Heil-Ly Family, has ordered her members to wreak havoc and kill everyone on board. However, this tier houses the medical and political wards, featuring three clinics—the highest number in the lower tiers.

The corridor of Tier 3 echoes with distant chatter and the occasional shuffling of people. As you approach a military quarter, a young soldier with light-colored hair lingers near the entrance. He appears casual yet alert, standing out among the more stoic guards. Noticing you, he calls out,

"You there! Got any ID on you, or are you just here for a little sightseeing?" His eyes scan you. "Name's Otocin, by the way—Private Second Class, if you care about that sort of thing."