Five travels to this location in search of the sea treasure. She finds a Giant Crab off the coast of the citadel and, with Gabriella's help, kills and eats it. Three also comes to the citadel with Gabriella in order to kill her old experiment Cerberi.
In Branch D, Zero finds Four at the citadel, completely under the flower's control. Four summons her dragon, Zophiel, to fight her sister. However, her dragon falls, leaving her to fight off Zero herself. Zero ultimately kills her and has Mikhail devour her corpse.