Most of the humanoid Abyssals are basically the ara-mitama (rough and violent side of a kami which usually has to be pacified for the nigimitama to appear) to the kanmusu's nigimitama (the functional, 'normal' state of a kami).
(Strictly speaking, the shinto terms also applies to all sorts of spirits, not just the spirits of kami, but in most context it refers to kami.)
Shipgirls, meanwhile, are pretty much composite kami assembled from the spirit of the ship and its crew.
The Abyssal Fleet represent and reflect a lot of thought and feelings don’t they.
Loss, Despair, Grief,
Regret, Guilt, Shame,
Humiliation, Fear, Pain,
Anger, Hatred, Fustration
Vengeful Desires, Unfulfilled Hopes and Wishes, Unfinished Business…
Hopefully the Kanmusu will be able to put these tormented souls to rest…
Zuikaku was not aware that Chiyoda was still alive... as she lay crippled in the water barely alive, she witnessed Zuikaku's final moments unable to do anything to help her...