The way The Locked Tomb uses cannibalism is so interesting, because while it does serve as a metaphor for intimacy, the series only uses it that way when it's cannibalism of the soul. Cannibalism of the flesh is either extremely limited, or straight up horrific.
Like step six of the Eightfold Word. It's literally presented as "consume the flesh," but Ianthe goes out of her way to specify that a single drop of blood is sufficient. The most unhinged act of intimacy in the series, and it's explictly the soul and only the soul being digested.
Human flesh is only consumed in any volume twice: John's post-apocalyptic survival cannibalism, and Harrow's delicious murder soup. Both those scenes are exactly the opposite of intimate, and about as far from erotic as you can get.
John and Alecto gorging themselves on anonymous strangers was debasing to everyone involved, and not something John ever wanted to be reminded of. Harrow's soup was a desperate attempt at self-defense, like an animal in a trap gnawing through her own leg. It horrified and disgusted everyone at the table, even Ianthe, the number one suspect at making it weird.
I love the overall effect of the layered symbolism, because it allows cannibalism to be explored both ways. Seperately, without one connotation implicating the other. Except for Babs, of course, who gets to be both.
