SMT5V Demi-Fiend 1 Turn (No Dagda/No Incense/No Repel Phys/No NG+/Over 50% Success Rate)

Firstly, I am well aware that I am not the first to do this.

Second, some explanations
I had previously done a 2 turn setup with a weaker Gogmagog linked below. That one could have been a 1 Turn as well, but would have required an extremely lucky damage range and a low odds random Dream Fist crit.
   • SMT5V Demi-Fiend 2 Turn (No Dagda/No ...  

I had since decided to make a stronger Gogmagog, taking advantage of newfound knowledge of how Warrior's Conception works, and while being pickier with Gogmagog's level up growths. And as it turned out, not only could it hit the needed damage benchmarks using only Figment Slash, but it could do so while averaging 60,007 across 7 hits, slightly more than the 60,000 HP that Demi-Fiend has, meaning the odds on the damage range was over 50%. Additionally, hit rate was about 99.75% on Figment Slash thanks in part to Xiezhai's Helmsman, putting the overall success rate of the strategy still above 50%, even if only slightly.

For those looking to replicate this strategy, I made the Gogmagog by setting up an Ongyo-Ki and a Zeus that, together, had gained a total of 132 Strength over their bases between them (Ongyo-Ki at 152 Strength, Zeus at 117 Strength), granting 19 Strength from Warrior's Conception. From there, I was extremely picky with which Gogmagog levels I didn't reset, only keeping levels that Gog gained 2 or more Strength on (though on 3 level ups he got 3 Strength).

For those looking for combat benchmarks, the strategy becomes possible at all at 152 Strength (though only technically). Any less and you could hit max damage on all 7 Figment Slashes and still miss the kill, meaning other more gamble-y skills like Dream Fist would be required. If you want a 50% success rate, I believe 164 is the minimum to get the average damage above 8,571.42 per Figment Slash.