How-Tsu: Weapon JB (3 Tsu, 1 turn)
It took a while to theorycraft, and even longer to convince my friend (player 1) to spend two runes on Tsu. Pulling it off took two tries, the first failed due to incorrect move order lol.
Don't expect more from me in the near future, I'll probably do some more once Tsunyame's Tsu gets up to 6*, but a few months ago I dropped my Salrath account which had the fully built Tsu - only revived it for 20 minutes today lol, it's going right back into cold storage.
~~~~~~~~
Units, skills, and gear used:
The Tsus all had Extreme Magic Bow and Slayer's Emblem, P2 and P3 had Monkey King's Vest and her exclusive hat, IDK what P1 had but it wasn't that lol. As for skills, P1 - Quick Step and Shadow Steal, with Back Stab for the memes, because she doesn't enter combat. P2 - Instant Flash and 3c, with Quick Step because she doesn't need to bring anything else. P3 - Quick Step, Shadow Steal, and Instant Flash are all required. I believe all three have a breeze enchantment. Something to note is that P1 and P2 both have a 4* Tsu, while P3 has a 6* Tsu. Only P2's Tsu has any casting done, but for her it's fully maxed.
Both TJesses had Teleport and 3c, with the 3rd slot not mattering. Only gear that matters, besides a good int accessory for a bit more damage, is a Scepter of Divinity.
Sword of Light and Shadow (4* BTW) had a pretty ordinary set of gear, Full Moon enchantment, Seal Guardian, Forbidden Armor, Vampire Mask, and Slayer's Emblem, but anything with 10% atk and 8% atk works for weapon and acc, and the armor/hat can be literally anything, the defense debuff didn't matter and forbidden never procced.
~~~~~~~~
I don't suggest using this strat for yourself unless it's for the memes, I have a more approachable strat, also 1 turn, in my How-Tsu JB playlist. (Edit: I thought I did, turns out I forgot to save the recording so I'll redo that at some point if I remember)
Tsu isn't really needed for any of these 1 turn strats, on the right side you can also use Gin, Elwin, Lost Ham, Wet Ham, and many others (just need to swap who has TJess and who has Neo Zeri on the right side). Left side, Luna also works, as do a few others, but if you have Tsu and have a couple of runes to spare, she's a simple option I suppose, many others need boots for extra mobility. Middle is probably the easiest to replace, as anyone who can move 3 blocks after attacking (Rozalia comes to mind, or Leon) or two blocks after attacking from 2 range (Technically even Liffany with her exclusive, but more likely Narm, Deedlit, or the aforementioned Lost Ham), will work if they can oneshot Ivar. Same for anyone who has 4 range on turn 1 like Lucretia and... is it just Lucretia? Beck at 6* I guess, and ∑ too, technically.