I've got a new idea for a new team I'd like to try. I don't have too much time at the moment, though, so if anyone else wants to do it instead, feel free to do so.
I wish to design a team completely around Yukari's Spiriting Away. Obviously, this will be a team geared towards end-game power, due to its obscene SP cost. I honestly believe it's a build-around-me spell that can be the best spell in the entire game if used correctly. I know I've made a few videos about it already, but I think I've merely just scratched the possibilities of what it can truly accomplish. So far, I've only used it for damage race all-or-nothing situations where I either win before the boss's next turn, or just flat-out lose. But what if I were to use it as a continuous engine of super-fast turns for not just attacks, but support spells as well? What if I were switching out the other three members without losing a beat of tempo with my combo, and still reaping close to 300% guage profit with each Spiriting Away cast? I think it's very doable.
One thing that I still haven't done in my videos yet is switch out characters as needed. There are lots of characters with 0% post-use gauge moves that I only want to use once or twice, not continuously like with heavy-hitting nukes. However, it's really not hard at all to fit in necessary switches. Observe:
Let's say I'm fighting Agastobrauma, and he decided to start off with Strengthen Jutsu. Agastrobrauma has way too much HP for me to kill it before it gets another turn, unlike Bloody Papa, so I can't just race it with damage. What do I do instead? My starting party will be Renko, Yukari, Yuugi, and Nitori.
1. Agastrobauma goes first, and uses Strengthen Jutsu.
2. Renko takes her turn, casts Galaxy Stop to spike Agastobrauma's SPD.
3. Nitori and Yuugi each take their turn, dropping their active guage to 0% with their power nukes.
4. Yukari casts Yukari's Spiriting Away. Battle guage filled since start of battle: 50%
5. Renko goes again, casts Debilitate.
6. Yuugi and Nitori each switch Yukari out and back in again.
7. Yuugi and Nitori still go before Yukari, and use their power nukes again.
8. Yukari casts YSA again. Battle guage filled since start of battle: 75%
9. Renko goes first again, switches herself out for Rinnosuke.
10. Yuugi and Nitori switch Yukari out and back in.
11. Rinnosuke goes first, because his speed is higher than Yuugi's and Nitori's. He casts World-Shaking Military Rule.
12. Yuugi and Nitori each use their power nukes.
13. Yukari casts YSA again. Battle guage filled since start of battle: 100%
14. Rinnosuke gets a turn, switches Yukari out.
15. Nitori's turn, switches Yukari back in.
16. Yuugi's turn, uses KO in 3 Steps (I let her instead of Nitori attack w/ 80% buffs because of Agastrobrauma's weakness to fire.)
17. Rinnosuke's turn, uses Start of Heavenly Demise (is this stronger than SGS with offense build after buffs? needs testing)
18. Nitori's turn, uses Megawatt Linear Gun.
So far, so good? Let's continue with a trickier scenario.
19. Agastrobrauma takes its second turn. For the sake of an example, let's pretend it uses its strongest spell: Enma's Lightning. It's powerful, but because of buffs/WND resistance/whatever, my party takes severe damage but survives.
20. Yukari's turn, casts YSA. Battle guage filled since start of battle: 125%
21. Rinnosuke's turn, switches out Yukari.
22. Yuugi's turn, switches Yukari back in.
23. Nitori's turn, switches herself out for Reimu.
24. Rinnosuke's turn, uses SoHD.
25. Reimu's turn. Casts Exorcising Border.
26. Yuugi's turn, uses KO in 3 Steps.
27. Yukari's turn, casts YSA. Battle guage filled since start of battle: 150%
28. Rinnosuke's and Yuugi's turns next, they switch Yukari out and back in.
29. Reimu's turn, switches herself out for Youmu (because Nitori is still injured).
30. Rinnosuke, Yuugi, and Youmu each take their turn, and nuke the boss with their massive delay nukes.
31. Yukari's turn, casts YSA. Battle guage filled since start of battle: 175%
32. Rinnosuke and Youmu switch out Yukari while Yuugi uses KO in 3 Steps.
33. Rinnosuke and Youmu each use their nukes.
34. Yukari's turn, casts YSA. Battle guage filled since start of battle: 200%
(Yes, I'm fairly confident I can get Yukari's SP high enough to cast YSA this many times by this point in the game. And probably a lot more times if I use some SP+ equipment.)
(No, Agastobrauma still shouldn't have its third turn yet if you've landed Galaxy Stop at the beginning. Enma's Lightning has a post-usage guage of 10%.)
You've now used 21 spells with 0% post-usage guage delay (not counting Yukari's Spiriting Away itself), and still have 3 characters with full guages ready to go for another 3 potential nukes and an active party with full HP, and you've only had to wait for the time it takes to fill the battle guage 200% (all characters start at 50% at start of battle). By comparison, if you had two tankish characters in slots 1-2 dedicated to swapping out 4 different nukers in slots 3-4, you could only use 14 such nukes in the same amount of time under perfect setup conditions, and you wouldn't even have anyone with a full guage (or likely full health) at the end there. That's the power and potential of Yukari's Spiriting Away: if you can keep it going, the speed that it affords your party is far greater than any other strategy that I can think of. The fact that you can still flexibly switch in support and healer characters like Renko and Reimu without missing a beat only makes this even more effective.
I used to think that Yukari's Spiriting Away was only good for sprints. But now that I've considered adapting it for marathon battles in the late game, I'm wondering just how much more of its potential I've yet to explore. I agree that you have to build around it to exploit its potential; you can't just use it whenever you want and expect it to be effective. But as far as potential goes, I believe it has far more of it than any other spell in the entire game.