Managed to clear with the help of a few strokes of luck!

Name-----HP---Atk
Hercules-7597/46572 (Ex slot: Sniper Shot)
Tyr------6423/46292
Krishna--5594/40343
Sol------7233/40709
Ramiel---6303/39892

Nemesis--5758/42332
Baal-----5576/38760

Assault: 95% (136 skill lvs + 27 directly from assault M/L) + 2 Pride (L)
Defender: 21%
And Rush (L) lv 2 (from 3* Ixion Bow whose sole purpose is to enable Herc usage for thunder with max burst multiplier)

Amaru (main)/Tiamat/Yggdrasil/Sphinx/Jormungandr/Meng Huo
Friend slot is a 100% Kirin

If Krishna and Baal seem a bit low, it's cause they're actually at 3*, not 4*. The original thinking is that I'd hold off on spending grimoires on them since I'd replace them sooner or later, right? This was way back when grimoires were in far lesser supply. At some point since then I've just flat out forgotten about that last limit break for them and it turns out that I still have not gotten a replacement for that 5th starting slot (which Krishna currently occupies). Baal's my choice today for that second bench slot since I was looking for as much instant offense as possible. I did not expect to resort to Baal here.

Krishna fell against the Demogorgon. If I had to lose someone there, she's probably the best case.

1st pivotal stroke of luck: Ramiel successfully inflicted dazzle on Jormungandr. Dazzle triggered once at some point, which later resulted in me being able to push into rage just shy of another overdrive, then having the special trigger overwrite the raging overdrive
2nd pivotal stroke of luck: The special trigger kills Sol, which actually improves my normal dps. At that point, with Caldo Luce recently reapplied and her heal on cooldown, she wasn't gonna do much for the next few turns. I was still stuck in rage then and needed offense to dodge the raging overdrive. In comes Baal. Baal unloads her skills.
3rd stroke of luck: I land the 33% chance for Baal to triple (3% base + 30% from her 3rd skill) in both turns I had before the raging overdrive. That plus.. maybe a double here and there? was enough to push into stun. And there's the win.

I picked up soul survives, 5 members survive, and 3+ SRs from this one. I may end up settling for 2 ori, as I don't think I can squeeze much more out of my thunder team as is. I'll probably have to give my light team a shot; I got good survivability pieces but my grid isn't at 'just throw light at it' levels.