His post was in response to a description of 70 gnolls being shredded by a Spirit Guardians spell. So in this case, the spell was already in place. Since it is centered on the caster, it doesn't take a genius to figure out who cast the spell. And since there are 70 gnolls, all of whom should likely be equipped with longbows, there's no reason to think that martial warriors can stop them all, or that the gnolls wouldn't simply fire arrows over the warriors at the cleric.
So it's far from a rubbish argument.
A caster with Spirit Guardians in place needs to get near the battle in order for the spell to be effective. And whether or not a caster lets anyone know he's a caster before the martials are engaged is going to vary by caster. However, I'd say that since it's a divine spell that we're talking about, and since clerics tend to be devout in their worship of their chosen deity, I don't know if I'd assume that their default stance would be to hide that fact. In fact, I'd say this kind of assumption is an example of players making decisions more about the game than their characters might make about the world.
Your assumptions about what kind of group anyone making these points must be a part of are totally unwarranted because again, this was in response to another poster, one who thinks that ranged combat is too great. So it's a specific example being discussed. There is no need for you to guess at how anyone else plays the game. Instead, discuss the 70 gnolls running to their death against a spell with a 15' radius centered on the caster.
This example isn't really about how smart the monsters are so much as how stupid they shouldn't be.
As the DM with the gnolls, I can tell you what the specifics were, so you don't have to guess (and especially not make guesses meant to strengthen your own discussion points).
The encounter was meant to trial the mob rules of the DMG, where the DM makes a single melee attack roll for, say, half a dozen enemies. The purpose was to see if characters approaching the end of tier II (I can't remember their exact level) are sturdy enough to withstand weak enemies numerous enough to justify the mob rules. Hence, I used regular Gnolls with their bites and spears but no longbows. Feel free to disagree with this, but please don't use it to make assumptions on the overall issue.
Another choice of mine was that any Gnoll that witnessed the death of an ally through the Spirit Guardian area would attempt to avoid entering it. But that these Gnolls would otherwise not know the aura's exact purpose. If they could attack somebody without a magical shimmer, they would.
Now, in order to get within their spear's short range, they must come awfully close to the area. This enables the Cleric to catch plenty of them by simply moving forward ten feet or so. So it's no surprise many were caught, either by charging into the field or by being too close.
Those who charged was slowed down by the spell's other effect, ensuring almost no gnoll survived to make melee attacks at all (since they need to survive two helpings of damage; an not inconsiderable amount of damage given that the Cleric cast the spell at his highest spell level; level 4 I believe)
At least one round there were probably two dozen ranged attacks at the Cleric. It wouldn't surprise me if he took 40 attacks in total. But with outstanding AC and actively dodging, very few were hits. And with optimized Concentration checks (proficiency and advantage) none came even close to disrupting his Spirit Guardians.
Had the Spirit Guardians failed, he could not have withstood all the incoming attacks himself. If he was super-unlucky the first Gnoll breaks his concentration; but more likely he would survive to bring back up the spell again. Of course, this would be noticeably weaker, since it would probably be cast at a lower level, and there would be no time to dodge. In all these cases, the rest of the party would have had to move in to help out.
As for the caster's position, this fight took place in semi-narrow underdark tunnels. (Either wide corridors or narrow rooms; the width and height varied mostly between 10 and 20 ft). Of course, I didn't have all Gnolls attack from a single direction, that would have made it too easy to stop them - I had placed four approach tunnels one of which came out in the chamber's ceiling.
The party had heard the gnolls yapping for a while, so they were not surprised. The Warlock felt it necessary to expend a Wall of Fire to stop the first squad of Gnolls, thereby giving everyone else a round to position.
The Cleric positioned himself so that no (or few) Gnolls could pass him by, if we include the 15 ft radius from the spell. He did so by moving right underneath the opening in the ceiling - making it rain dead and dying Gnolls all over the place.
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In this case, I freely admit that given other terrain and effective ranged weapons, Spirit Guardians would have played a much diminished role.
But it certainly is an anti-test-the-mob-rules spell!
And it kind of nailed down my belief that there is an urgent need of humanoid stat blocks in the 30-50 hp range.
My other "swarm" encounter (that came soon after the Gnoll fight) worked much better, if by "better" we mean the characters were severely challenged and the players had to pull out every trick in their book to survive. Or in other words, the kind of encounter that make the game worth playing
It notably featured homemade Grimlocks where I blatantly ignore the impractical idea of bounded accuracy and instead make it work.
But instead of me guesstimating the CR of these monsters, how about I show the encounter to you, and you can judge for yourself
1
Fomorian (MM136, but large, not huge) riding on an
Umber Hulk mount (MM292) crashing out from a wall while the party descends a vertical shaft (one with lots of cracks and passages). Behind it, a dozen
Elite Grimlocks (MM175 plus below) spend their "surprise round" action to swarm out and down to make area spells difficult. The only actual attack on the first (surprise) round would be the Umber Hulk's gaze, IIRC.
Elite Grimlocks (three varieties, four each):
Grimlock Cannibal: 25 hp, Speed 40 ft; Bone Club +5 for 1d6+3 dmg, Grisly totem (+5 AC single-use; like a Shield spell); Blood Frenzy: bonus attack against wounded foe
Grimlock Brute: 40 hp, Two-handed Spiked Bone Greatclub +6 for 1d8+4 blunt dmg, on ⚃-⚅: nasty gash for 1d8+4 extra slashing dmg; Bloodied Fury: bonus attack when bloodied
Grimlock Warrior: 30 hp, dual-wielding two Spiked Bone Clubs: two attacks at +5 for 1d6+3 dmg, on ⚄-⚅: nasty gash for 1d6+3 slashing dmg
This is my kind of interesting monster variety. You'll note the terms "wounded" and "bloodied" - they mean "at less than max hp" and "at less than half max hp" respectively. All three varieties have their own way of generating twice as much damage (Cannibals making a second attack if foe is wounded; Brutes making a second attack when bloodied themselves; and Warriors always doing two attacks). Also, there's the use of variable damage (for the spiked clubs) to further increase the players' excitement.
And don't forget the "evil" synergy between how the master and his steed both having gaze attacks, and his servants all being blind and thus immune! Let me tell you, these stats combined with the fact the monsters achieved total surprise, made for a fight that was as memorable as it was difficult! The players were visibly shaken once they had vanquished their last foe. If I remember, three out of five characters were down to single-digit hp! Even better, it was reasonably fast - it didn't drag out into a stalemate or something. Just a desperate and very grisly deathmatch
![Devious :] :]](http://www.enworld.org/forum/images/smilies/devious.png)
All of these mechanics are shamelessly lifted from 4E, whose Monster Manual in my opinion is a vastly more interesting and useful D&D supplement than the 5E MM.
Now, what CR would you peg something like the Grimlock Cannibal...?