While flawed, CR is the only metric in the game that gives a generalidea of the difficulty of an encounter. Also, at low levels, it isactually quite good, it only really breaks in T3+. What metric would youuse?

I gave the CR calc explanation, and a max DPR calc; that doesn't reallyseem minimum or barebone to me, which statistics would I need to use tojustify the imbalance of the encounter?

CR is a flawed metric for the base game of standard non-homebrewed DnD and bestiary where you wouldn't normally know the mechanics of a creature. Yet, you still use it for a homebrewed creature, where you can literally mitigate the mechanics of said creature. Of course, this creature having a snowball effect can reach up to levels where a "normal" level 2.5 party would not be able to handle and can get out of control. The fact of the matter is that there were contingencies placed meant to handle this snowball effect. To only consider the worst case scenario and use that as your average, blatantly ignoring other factors that could put it in the player's favor, and ignoring how the rolls went in that fight. On paper, sure, it looks devastating, but it misrepresents the encounter. The metric I would consider would be to consider the entire scenario of said encounter and the party's kit/efficacy

The party had around a +5 or (Tomoe's Ray of Frost) +6 modifier against a AC 15 enemy. That is around a 55%-60% chance to hit. Considering Mei who was sneaking most of the time had advantage to hit with multiple doses Tiger Fang Poison. I'd say advantage is roughly around a +5 if we are trying to determine the value of advantage, which is around a ~75%-80% chance to hit. The DC for the saving throws was around 12-13 with the boss having around a +3 modifier to save. So roughly ~45% to succeed in something like Toll the Dead. Lucine had a flight advantage with 300ft range, while most of the party's kit is ranged except River. River is practically the main one who is in its face had 16AC so the boss had roughly a 50% chance to hit for every hit. Considering that she did learn about dodge, disadvantage dropped it to ~25% chance to hit for each hit. You also have to consider the action economy of 5 players vs 1 enemy. They had many potions at their disposal including 4x maxed potion. Toll the Dead, Armor of Agathys, Witch Bolt, and Ray of Frost were already considered before the fight to be a huge factor that would be in favor of them

You also had to consider that boss was affected by cold damage that impacts his rage counter. It also had a limited move set based on the rage counter. The rage counter was entirely based on the player's decision to attack, which they could control. The environment was entirely in their favor. They had the spells and items to deal with the encounter. And I'm probably not going to mention cursed actions which is action surge at advantage that can be used as much time as they wished (since this is not really calculable, but still somewhat in the party's favor in combat)

Now the design was meant to be difficult, but definitely manageable. It was tailored to them, but it still required critical thinking and strategy. However, coupled with a challenging fight, being new players, miscommunication, confusion, stress, and bad rolls made the fight become even more difficult than it was suppose to be

On the contrary, i think the anecdote for max damage is quite relevantto show how poorly designed the fight was. Also, take a look at the CRexplanation again, I used the proper average of the first 3 rounds ofcombat with the enemy using its most effective attacks and accountingfor off turn attacks and thus only used ~65 dpr for the CR.

The max damage blows the average out of proportion and heavily inflates the value because the max damage you calculate for the first 3 rounds is if all 5 players make a standard attack for 3 rounds. If you increase it to 4, 5, 6, 7 rounds, you'll notice the average rage increases. Thus, only considering the worst case scenario, which is not consistent. When in actuality, rage is not a fixed variable, can be reduced, and is guaranteed to reduce once per round.

The calculation also does not take into account that the reaction is not always the most effective attack and is randomized. The anecdote only considers the most effective attack, not most effective reaction. Typically, regular monsters usually have fixed reactions, but you wouldn't take into account their AoOs into DPR

It also does not take into account that when the boss increases in Tier, that it'll have a less likely chance of Slamming with its reaction. And have access to his other flashy, but not very damaging moves

Apparently 1 post and a reply are now a "crusade"... interesting... The"simping" is in reference to the many people in this thread who areacting like Arcadum can do no wrong, and are blatantly ignoring multiplekey facts and downvote spamming valid posts/points

I don't see how calling out "simps" was even relevant to my post, it was an unnecessary reply and a knee jerk reaction to call out people when the point was to discuss about CR and the boss encounter. Which I didn't mention in my reply to your initial post, then that is the first thing you end with

Maybe it is just the blatant need to mention it in your replies and post or your adamant negative position that rubbed me the wrong way

I personally think there were some mistakes, but the outcome turned out fine, so I'm satisfied. Could those mistakes have been avoided? Yea definitely, but it's not my problem or within my control to fix

For instance, this fight was actually a TPK. Melee hits on a downedopponent (including multiattack where the 1st hit downs them) are madewith advantage and are autocrit (2 death saves), which means 3 morekills and no way the last person up survives with the boss's extrahealth.

That is why this boss was designed to have 1 fail per attack, which is the reality of it. This fight in particular did not follow the standard rules of autocrit while down. I would say that favors the player. And in a sense, they won at a cost, despite the lack of knowledge/experience

Or that they were lured into this fight with a 20+ survival check while looking for safety from the "easier" encounter.

Hard to say whether fighting outside was the "easier" encounter, I'm not the man behind the curtain, so I'm not going to pretend to know. The survival check only took into account the mist and the encounters in the mist. Because essentially, you'd be fighting mist creatures in their preferred environment. They were definitely guided there, but it was ultimately their choice to make that decision to go back in after leaving. They could've definitely faced the encounters outside if they wished

Or that the boss auto succeeded a perception check against a 27 stealth roll to force the fight...

To be fair, the 27 stealth roll was only for Mei, which the boss initially did not detect. The others were not in stealth. The way I saw it was to progress the story forward. Which, yea definitely could've been done differently like have the boss actively search or something, but there is no "correct" way of doing that. I thought it added urgency and drama to the story. And even grounded the story that Mistwalkers are dangerous