The sixth book in the 'All Souls' trilogy, 'The Book of Life,' actually wraps up the series—so there’s no book 6! But if you’re curious about the core cast, it’s still all about Diana Bishop, the witch historian, and Matthew Clairmont, the vampire geneticist. Their chemistry is chef’s kiss—equal parts scholarly debates and supernatural tension. Supporting characters like Marcus, Miriam, and Gallowglass add layers, whether it’s through vampire politics or witchy family drama. Even secondary figures like Fernando and Phoebe get memorable moments. Honestly, Deborah Harkness’s strength is making every character feel essential, not just filler. I still flip through my dog-eared copy just to revisit their banter.
If you meant another series with a similar title, though, I’d need more details! The 'All Souls' universe is so rich that fans sometimes mix up spin-offs or fan theories. Like, there’s that fanfic anthology 'The Blackbird Chronicles' that imagines Matthew’s past—could that be what you’re thinking of? Either way, the original trilogy’s characters stick with you long after the last page.