The Captain's Counterattack in Honkai Impact 3rd

Why does Rita's cleaning mop keep getting stolen on the deck?

Why is the Hyperion's deck so smooth and shiny that multiple Valkyries keep slipping and falling?

And what is that shadow that suddenly appears in midair at night, doing the splits with its head gleaming?

Behind all this, is it the captain's moral decay, or the cleaner's loss of humanity?