Here's the Abyssal Sibriex From Mordenkainen's Tome

This....thing...is....AWESOME!

 

[Parmandur]

If the level 18 party has even an inkling of what they are up against in the sibriex, they are going to nova that thing into paste.

The only way it's dangerous is if it's the last of the mythical "6-8 encounters per day" or if there is some kind of serious terrain advantage that allows the sibriex to become straight-up untargetable on other creature's turns.

In both cases, it doesn't need to have Legendary actions or resistance to be a serious threat. I think Legendary should be reserved for creatures that are encounters unto themselves, because the "field or green room" no longer counts as "favorable terms."

So, it is only dangerous in the circumstances for which it is designed to be used? Shocking turn of events.

 

[CapnZapp]

deleted

 

[Dausuul]

If the level 18 party has even an inkling of what they are up against in the sibriex, they are going to nova that thing into paste.

So, they just blew a bunch of resources to nova a Medium-difficulty encounter. Okay. I don't see the problem here.

In both cases, it doesn't need to have Legendary actions or resistance to be a serious threat. I think Legendary should be reserved for creatures that are encounters unto themselves, because the "field or green room" no longer counts as "favorable terms."

I agree that a legendary creature should be able to function as an encounter unto itself. But where are you getting this idea that a Medium encounter should be a "serious threat?" If you want an encounter where the monster has a significant chance to win, you should be looking for a Deadly encounter, which a lone sibriex is not expected to provide for a party of level 13 or above.

How well can a 12th-level party handle a barrage of DC 21 action-denial spells, coming in at 3 per round?

 

[CapnZapp]

One of the characteristics of intelligent monsters is they have lots of minions to fight for them.

I must have missed the rule that says the Intelligence modifier is added to Challenge Rating, simply because DMs always surround them with minions.

Going up against a party of adventurers solo is pretty much the definition of low intelligence.

Going up against a party of adventurers solo is pretty much the definition of an awesome BBEG!

 

[UnknownDyson]

If the level 18 party has even an inkling of what they are up against in the sibriex, they are going to nova that thing into paste.

The only way it's dangerous is if it's the last of the mythical "6-8 encounters per day" or if there is some kind of serious terrain advantage that allows the sibriex to become straight-up untargetable on other creature's turns.

In both cases, it doesn't need to have Legendary actions or resistance to be a serious threat. I think Legendary should be reserved for creatures that are encounters unto themselves, because the "field or green room" no longer counts as "favorable terms."

But its stupid.....assuming you're in the Abyss and the DM isn't hand waving you through the plane there is no way that you wouldn't already have been in 2-3 encounters with anything from Glabreezus to a Balor and an abyssal horde. Creature's like this have lairs, there should never be a time where you aren't fighting this thing in addition to it's wretchlings and 3-4 hezrous (or whatever it has on hand).

Example: 18th level party vs Sibriex in it's lair alongside 5-10 wretchlings, 3 glabreezu, 3 hezrous, and a marilith. After 2 rounds more demons continue to wander into the fight looking for an easy meal (roll on a random demon table, because this is the Abyss).

Anything that isn't something like this is either the result of plot events (some god teleporting you in front of this creature while it's alone, or a demon lord that you're somehow on good terms with gives you the creature's location and it's behavior patterns) or the DM is purposely downplaying the monster to pad the party's exp and collective egos (nothing wrong with this) but if you're trying to seriously run this monster then nothing you said above makes any sense.

 

[Istbor]

This monster is mean. I like it.

I think I am going to enjoy using it in my Homebrew. Just need to let the players gain a couple levels so this won't one-shot them. Heh.

 

[Mr. Wilson]

But its stupid.....assuming you're in the Abyss and the dm isn't hand waving you through the plane there is no way that you wouldn't already have been in 2-3 encounters with anything from Glabreezus to a Balor and an abyssal horde. Creature's like this have lairs, there should never be a time where you aren't fighting this thing in addition to it's wretchlings and 3-4 hezrous (or whatever it has on hand).

Example: 18th level party vs Sibriex in it's lair alongside 5-10 wretchlings, 3 glabreezu, 3 hezrous, and a marilith. After 2 rounds more demons continue to wander into the fight looking for an easy meal (roll on a random demon table, because this is the Abyss).

Anything that isn't something like this is either the result of plot events (some god teleporting you in front of this creature while it's alone, or a demon lord that you're somehow on good terms with gives you the creature's location and it's behavior patterns) or the DM is purposely downplaying the monster to pad the party's exp and collective egos (nothing wrong with this) but if you're trying to seriously run this monster then nothing you said above makes any sense.

Why would you go to the Abyss without a plan? Planeshift over to the Abyss and hole up somewhere. Likely in an extradimensional space. Scry over and over again until it works, watch 'till it's relatively isolated, planeshift in, decimate it, planeshift out. If we're talking about 18th level characters.

12th level characters have a bit of a harder time, given lack of access to planeshift, so it's assumed we fight it on the material plane in it's liar. In which case, you slog through the dungeon to get to the BBEG. There may be a few low level minions with it, but unless you're tossing 2-3x the xp budget of the party at them at once, you can't go hog wild with minions.

 

[Sacrosanct]

Intelligent monsters can't really be more intelligent than the DM who is controlling them...

While true, the DM has access to all information, including info that monsters wouldn't normally have. However, if a monster has an INT of 25 (smarter than any person I know of), I as the DM will allow the monster to have access to some of that info with the assumption that because it's so smart, it had ways of getting it that I as the DM with an INT of lower than 25 might not have thought of. For example, this creature would probably be aware of the party, and have plenty of time to plan and react accordingly.

As the DM, it's our JOB to put effort into playing the creatures and monsters and NPCs appropriately. If all you (general you) want to do is put stat block against stat block, then you're not playing the game as designed, and have no right to complain.

 

[UnknownDyson]

Why would you go to the Abyss without a plan? Planeshift over to the Abyss and hole up somewhere. Likely in an extradimensional space. Scry over and over again until it works, watch 'till it's relatively isolated, planeshift in, decimate it, planeshift out. If we're talking about 18th level characters.

12th level characters have a bit of a harder time, given lack of access to planeshift, so it's assumed we fight it on the material plane in it's liar. In which case, you slog through the dungeon to get to the BBEG. There may be a few low level minions with it, but unless you're tossing 2-3x the xp budget of the party at them at once, you can't go hog wild with minions.

Another convenient scenario that favors the party. I'm not going to go back and forth with you too much because it seems you're pretty firmly entrenched in the idea that pcs should steamroll through everything with plot armor. You're arguing from the perspective of game mechanics, exp and hit points, things that are outside of the purview of an actual campaign world that a dm tries to arbitrate with some level of consistency and realism. There is no exp budget for the plane of infinite demonic nightmares spawned for the purpose of ending creation. This, is what i mean when I say you just create scenario after scenario in the pcs favor.

You want to planeshift in to a Sibirex flesh pit? Ok, maybe you have surprise, maybe as you said, it's alone (for some reason) and the battlemaster knocks it prone and the party novas it, as you said. Or maybe you all roll a madness saving throw as soon as you pop in? Just as you constructed the perfect scenario (or so you think) for the party to come in and kill the demon on it's home turf, the dm can respond in kind. And if you're planning on using the Sibirex for any kind of set piece encounter or end of arc fight the party isn't just going to be able and pop in and steam roll everything, it's not that easy. But, maybe that is what you're used to.

 

[Dausuul]

Why would you go to the Abyss without a plan? Planeshift over to the Abyss and hole up somewhere. Likely in an extradimensional space. Scry over and over again until it works...

It will never work. A successful save versus scrying prevents you from casting it again on that target for 24 hours. So, on the rare occasion that you slip scrying past the sibriex's magic resistance, the sibriex only needs one shot of LR to block you for a full day. And then it recovers its LR and can block you again tomorrow.

And if you do somehow force the spell through (using multiple casters, let's say), the sibriex has truesight. It can see the scrying sensor. It's not going to wander off into a nice isolated area for you to massacre it.

12th level characters have a bit of a harder time, given lack of access to planeshift, so it's assumed we fight it on the material plane in it's liar. In which case, you slog through the dungeon to get to the BBEG. There may be a few low level minions with it, but unless you're tossing 2-3x the xp budget of the party at them at once, you can't go hog wild with minions.

Then you've got 12th-level PCs facing hold monster, feeblemind, and command three times per round, starting after the first PC's turn, at save DC 21. The sibriex doesn't need minions to lay waste to a 12th-level party.