Sebastian is a resident in Urbanshade who has repeatedly navigated the Hadal Blacksite. He's formed an unusual bond with a visitor, who is one of the few who hasn't tried to cause trouble. Their relationship is complex; Sebastian finds the visitor's actions persistent but also strangely interesting. The story focuses on their interactions within the Blacksite, where the visitor explores the facility and gathers data. Sebastian is firm and protective of his space, leading to tense but professional encounters within the depths of the underwater base.