Ok, I’ll bite. Does it feel like the success rate goes down if you only play normal at 95-99%? I find my success rate always goes up in approximately the same proportion to the stated odds, but of course I don’t expect that if I see 85% at the start of an epic round that I’ll see 85% straight through to the end and finish up with an 85% shot of winning all 5 locations. All it takes is 2 losses in a location and you are out.

I’m gonna go ahead and break out the math to show you why you didn’t stand a 90% chance on winning the whole thing even though it said it was 90% at the start. I’m going to assume you are playing on hard, as 90% on epic would require some pretty great gear from the outset.

hard 1: 675/(675+75) = 90%

epic 1: 1800/(1800+200) = 90%

So, let’s assume you have an average combined score of about 675. Your chances of winning 2 of 3 of the first round is:

.9 * .9 * (3 - 2 * .9) = 97.2%

Even better, now we are at 97.2% chance of winning location 1.

hard 2: 675/(675+92) = 88% * note that these are truncated in game, even 88.99% would end up 88%

hard 3: 675/(675+104) = 86%

hard 4: 675/(675+128) = 84%

hard 5: 675/(675+150) = 81%

Hmm, that 90% turned into 81% by location 5. Now to further complicate things, let’s look at the amount required to win at least 2 of 3 stages at each location.

hard 1: .9*.9*(3-2*.9) = 97.2%

hard 2: .972 * .88*.88*(3-2*.88) = 93.3368832%

hard 3: .933368832 * .86*.86*(3-2*.86) = 88.3609072828416%

hard 4: .883609072828416 * .84*.84*(3-2*.84) = 82.298642155980403507%

hard 5: .82298642155980403507 * .81*.81*(3-2*.81) = 74.514671983583464982%

So from that lofty 90% chance at the start, now you are down to only a 74.5% chance of winning all 5 locations. If you stopped after 1 or 2 locations, your success would be even better than the initial 90%, but as you continue, the tiny chances of failure will keep compounding and making your overall chances look less positive.

Note: this doesn’t factor in buffs and debuffs, that makes it all more complicated yet again, nor does it factor in that the numbers won’t all be 675, they’ll change for each sword pairing and with each action and direction of attack, but this will give you the ballpark numbers to see why 90% turns out less than that as you try to finish location 5. The difficulty also increases with each win in a location, up to the cap (195 for hard), and each location will also be further capped by the next higher location’s difficulty (1 <= 2 <= 3 <= 4 <= 5).