Advice on legendary book use
I find myself with 38 legendary books, but I'm not sure who to spend them on. Right now I'm thinking my priority is Sethallia, Rhazin, Hurndig and Candraphon in that order. That'd add up to 28 to 46 books to get what I'm most interested in out of them, so I should be able to get at least the first 3 done even if my luck with the skills the game gives me suck. I've listed the ones I have below, as well as how my reasoning for them goes. Feel free to ignore/correct/comment as you see fit.
Minaya:
I would really like to get the cooldown down on her A3 to make her a more consistent healer, but that's about all the books would be good for. I'm also not so sure I actually need her, between Apothecary and Sethallia, since burst heal tends to be more important in my experience, and their cooldowns are much lower. Any book that doesn't go into A3 would be quite a waste. 4-14 books required, but probably quite inefficient use.
Candraphon:
I'm lacking in AoE champions, so getting his A2 cooldown reduced would be very nice to deal with waves. Being a damage dealer, the bonus damage on both the A1 and A2 would not hurt either. 5-9 books required for the A2 cooldown, so relatively cheap.
Sethallia:
I'm looking to use her as a replacement for Apothecary, with the cleanse helping out in locations like the spider. A2 cooldown is the priority, but both the buff chance and the cooldown of A3 would be great too. Buff chance on her A1 would also be nice, but 50% to 60% isn't that big of a deal or worth the 3 books if I can avoid it. 7-10 books required for maxing both A2 and A3.
Hurndig:
I'm torn. I'd want his debuff chances to hit 100%, cooldowns would be nice, but damn would it be expensive to fully book him. I'm sort of curious about his performance in spider, but I suspect I'd have to manual to get the most utility out of him (e.g. manually A1 on weak spiderlings to get his A3 cooldown reduced). For locations with less cannon fodder for him to feed on, the cooldown on A3 would be much more interesting. 8 books minimum to get just the debuff chances up, 11 to get the cooldowns as well, and worst case 15 required.
Scyl:
Will get her in a couple of weeks. She seems like she can do her job pretty well without books, but getting the debuff chance and cooldown up on her A2 couldn't hurt. 6 turn cooldown on her revive should be fine either way, and 30% to 50% chance for a 15% turn meter reduction doesn't seem worth worrying about. 5-11 books for her A2.
Drexthar:
Ready for fusion, just waiting for an event to get points. Like Scyl, not sure how much different the books would make. I'm mainly looking to use him as a spider tank, and while increased provoke/atk decrease chance on A2 and HP burn chance on the passive would certainly be nice, I don't really know if it's worth spending books on. 8-11 books to max A2 and passive.
Ruel the Huntsmaster:
Also ready for fusion. Not sure how to use him but he'd be my only spirit AoE nuker right now. I would imagine I'd want his A3 maxed to keep the hex active, which could be as cheap as 2 books. Cooldown on his nuke would be nice, but that's another 5 books. 2-11 books for A3, or 7-11 for A2 and A3.
Rhazin:
I'm one rare away from being able to fuse him, but might as well include him since it shouldn't be that far away. Getting his A2 to 100% chance would be my goal, with the cooldown being an added bonus. A3 has such a long cooldown that 1 less turn doesn't seem like a big deal. The chance on A1 wouldn't hurt either, but not a priority. 5-12 books.