I have a story that I'm planning to write (kind of like a Yorkshire-set Dresden Files, but with some major differences), and there's a crime family run by seven sisters, all of whom are powerful witches. Most die early on but three end up becoming main antagonists in later volumes. I could have had each sister embodying a particular sin, especially considering the main villain is working with Lilith (who is a demon, relating to lust, the first succubus, and first wife of Adam before Eve came along).
And then I realised that this wouldn't work, because Lust would have to go to two of the sisters in particular, who are both openly lesbian and also into incest. And it wouldn't work having them both embody Lust, because then I'd have to add another sister for the final sin, or miss a sin out... Ah well, I guess I can fit it in somewhere, perhaps

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