D&D 5E I think I am going to stop using solo monsters.

[Lidgar]

If the Marilith was spying on them, wouldn't she be prepared to be summoned? Possibly it would have access to such mundane magic as a potion of invulnerability to quaff before it was summoned?

Another thing to remember on Mariliths is that they get to parry one melee attack each turn in a round, so for each PC attacking it with a melee attack, it's first attack is versus AC 23.

But yeah, 8 5th-level PC's should blow through plenty of high level CR creatures that don't have lair actions.

 

[Oofta]

I'll just echo what others have said, this was an easy fight so it's no surprise it wasn't a challenge.

If you have a large party, you have to beef up solos a bit.

Give them more legendary actions - my rule of thumb is 1 or 2 legendary actions less than the number of PCs.

Don't set up situations where they can be trapped and/or surprised (or account for it in your calculation). Getting to pre-buff increases the CR of the party by at least 1 or 2 levels, much less getting in a surprise round.

I don't use solos very often, but when I do I have lair actions (with a bigger group probably multiple lair actions) and the number of legendary actions can exceed the standard 3 since the rules are built around a 4 person party.

 

[Gadget]

This may be somewhat orthogonal to the issue at hand, but how did 5th level PC's summon a marilith? I'm not up on the latest summoning stuff, but I'm not aware of a way to do this outside Gate (and you need to know the true name?)

 

[Reynard]

For the record, I am not super upset about the Marilith fight, and I recognize the advantages they had in being able to prep (since I enabled it). My point is more that I don't really trust the CR system for 5E in general and specifically scaling it to a large party. It seems like action economy is the most important factor in combats and doubling the usual number of PCs is an exponential increase in capability. I am going to try and fix the way I operate as a DM, not try and "fix" the system.

What I will be interested to see in how a large group of less dangerous creatures affects play versus the big group. The PCs are about to accidentally walk into a hive of a dozen intellect devourers, and they have no idea.

 

[Fanaelialae]

It seems to me that, given she could spy on them via their items, she would have known about the plot and ambushed them while they were preparing (with minions in tow).

That said, I have found that solos are more impressive when they have a few minions with them (even if the minions are relatively inconsequential). Even the world's best quarterback wouldn't stand a chance against so much as a high school football team. But you put a great quarterback with a sub par team and he can make them shine (the same can be said of a great team and a sub par quarterback).

 

[Reynard]

This may be somewhat orthogonal to the issue at hand, but how did 5th level PC's summon a marilith? I'm not up on the latest summoning stuff, but I'm not aware of a way to do this outside Gate (and you need to know the true name?)

In game details. It was a specific marilith (technically it was The Marilith but that's just because I like using creatures as unique) and the party reverse engineered her connection to the cursed items, yada yada handwavium.

 

[Valetudo]

I think calling them solos was a mistake on wizards part.

 

[Yunru]

I guess "Boss" was too video-gamey?

 

[Lidgar]

I suspect a dozen intellect devourers will be deadlier, unless they are tightly grouped together and vulnerable to area affect spells. Also, depends on how great the party's saves are...

 

[Illithidbix]

And this day will be remembered as the day that the many stood against the few, and were triumphant!