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Starting TOBT, you’re still on the more sane side of canon. JUST YOU WAIT.
When to read Pandora and Vittorio? That’s a good question. Other ppl may have different answers for you, so anyone feel free to reblog this w/ commentary or send me a message on this.
Pandora
This is the story of Pandora, who was with Marius for quite some time, so I would read this one right before Blood and Gold (which is Marius’ story) so that her perspective is fresh in your mind when Marius starts talking smack about her. AR wrote Blood and Gold after Pandora, so she had to keep that information in mind, too.
Vittorio
HONESTLY, I don’t see that Vittorio really fits into canon at all, I think the Coven of the Articulate are mentioned briefly in his book? His story won’t spoil any of the other books, bc it’s completely separate from theirs, so I’d leave it till later. After Blood and Gold. Maybe even after Prince Lestat, since he’s not in that book, either.
When I started the series, the first 4 had already been published, and I read the fresh VC in the order they were released. This meant that I read Pandora between MtD and TVA, not really ideal placement, as, if I recall correctly, she has only brief cameos in those. I read Vittorio between TVA and Merrick, and I don’t think he appears in either.
Back then we read everything immediately, fearing every VC novel would be the last; trying times. Hope this helped ^______^