Level 5 Party, CR20 Monster?

[Eddieddi]

So, I'm part of a level 5 full mythic game (teir 2 mythic right now). and I'll skip the backstory as to how we got here, but it was heavily railroaded that we SHOULD be doing this. but it's culminated in the party of 4 of us, 2 spell casters, a bard and a tank, facing off against a Balor, (CR20 Demon who can summon other demons). I'm playing the tank, and I'm confident that I can protect us, at least for 4 rounds. but the dm keeps insisting that this is 'level appropriate' for the party. He's given us a level 10 cleric and a level 10 fighter NPC to back us up. I trust the DM (as far as any player can trust the DM that just gave them a CR20 monster at level 5) but most of the party have spent the week running up to our next session planning their get away. Our DM said this was a 'suitable challenge' to let us level up and give us our next mythic teir, however I'm starting to feel like it's just a forced TPK.
Our DM keeps insisting that he's got years of experience DM'ing, but I feel this is his first mythic game and I don't know how to tell him he's being a -insert expletive of any kind- here. while keeping him onside AND getting the party behind me on the whole "You shouldn't be doing this."
Does anyone have any suggestions as to what we should do? or if I should just let it all roll past me?

[Dhuraal]

If you trust him and have no reason to worry other than what a Balor is in it's purest book stat definitions, before assuming he is trying to screw you over, I would ask; do you think maybe it is a modified/nerfed Balor? Maybe it is the "teenager" equivalent (if they exist). Or it is already wounded?

[J-H]

Nothing stops a DM from adjusting monster stats. Maybe it's a dude named Bay Lore, and he's just a 12th-level wizard with Polymorph. Or maybe this one is restrained in some fashion or debuffed?

If it's a TPK, he may have a plan for you to get resurrected with a power-up and/or divinely-granted quest to keep the railroad moving.

[Eddieddi]

I hope you guys are right. The issue is from what I've heard from the other players (I joined the game late on a invite from a friend in the group) he's all up for giving them near-impossible encounters just for ****s and giggles, A example of this was when the group was level 3 he gave them 12 level 6 goblins, 2 of which were mounted. I'm more asking for 'how do I bring up with the DM that this isn't the best way to inspire confidence or trust with players?'

[Inevitability]

The only explanation I can think of is that he thinks 4 level 5 PC's = 1 CR 20 monster. If that's not the case, politely direct the DM towards this thread and pray he'll see he's wrong.

[Honest Tiefling]

I'd go through with it. Either the encounter is fine, in which case, good, you didn't leave. Or the encounter is crap and you know first hand without relying on rumors if you want to continue this game. What's the worst that can happen, a death for a character in a campaign you should leave?

[Willie the Duck]

I don't quite know what mythic games are, but unless that involves some kind of immunities or altered play, this sounds like either a fake-out or a tpk. The at-will abilities of a balor (blasphemy, dominate monster, insanity, power word stun) are almost all save-or-die or save-or-out-of-action effects that no one in the party could hope to consistently save against. Nor is it a CR20 monster with an epic weak spot (Tarresque against flying opponents). If this is truly a balor (which I suspect it might well not be), then you aren't supposed to beat it through use of combat ability.

[Âmesang]

Could be a grappling barbarian named Bálor (https://en.wikipedia.org/wiki/Finn_B%C3%A1lor), but even then you have to be wary of his coup-de-grâce. :smalltongue: