Intel

This post talks about (b), the first wave of minions sent by the higher intelligence below, which is loosely based upon the monster shown.  Very loosely.  Any magical creature ought to have a higher intelligence, to start; a mage's intelligence.

And while I accept the three hit dice, I'd prefer to make the "lake hag" a 7th level mage besides, with commensurate spells and an additional 7-28 h.p.  I'll keep the fright and the glance, they add nuance.

I never have any troubles with remaking monsters in this manner.  Players aren't entitled to "familiar monsters" or the knowledge of their stats in any degree — they're entitled to exactly as much information as Frodo had about Shelob, or as Ahab had about the white whale, or for that matter as much as Luke had about Darth Vader.  Basically, it's a creature and by the rules of the game it's more or less killable ... but what it can do or how many blows it takes to kill it, NO, the players don't get to know that ahead of time.  Doesn't matter what the monster is.

In our scenario of the players venturing down through the dungeon, stumbling across warm pools of water and inexplicable clouds of moths, they've already announced their presence to the lake hag, or Witch ... and she, in turn, has dispatched her minions, as I've explained.

As the DM, consider how this is best played.  The minions are most likely stupid: they exist in a lifeless, soulless place, under the thrall of a creature so hideous that to look at her produces crippling fear.  Their origin is uncertain.  But they are certainly obedient ... and while stupid, the Witch knows what they are, and their limitations.  It's our part as DM to play out the forward going scenario as though we were her.  It is, in effect, like a military campaign.

One might argue that the former princess, as the Witch once was, was not a military commander; but this is also not her first rodeo, and she's had 25 years to consider what she'd do if her lair was ever invaded.  Plus, she possesses the mind and soul of the former nobleman who once ruled the area — and what was able to learn from him, or how she does it, is entirely up to us.  I've already stipulated that the Witch is intelligent.  She has mooks that she can use like soldiers, even if they are merely strange amphibious and jelly-like humanoid creatures.  She may possess clairvoyance, as a 7th level mage, enabling her to witness how the "first wave" of attacks goes.

The first wave is never her whole strength.  It's always a means to collect "intel," in the sense of how long does it take these strangers to waste 15 mooks?  What powers do they have?  Who takes the lead in the fight?  Who hangs back?  Does a crowd of mooks put them off, or whet their appetites?  This sort of thing.

Now, as DM, we already know all this.  We've watched the party fight a number of times now, and we know which character is which class.  So we're not actually learning anything about the party.  However, as DM, its important that much of the time we "play dumb" when running enemies against the party, since the enemies aren't supposed to know what we know.  So with the first fight, that's how we run it.  The mooks arrive in the party's company at some point during their descent, with the players hearing them coming, and there's a battle.  They rush in rather stupidly, without planning, because they're meant to die.  Presumably, the Witch can produce more.  Or at least, these are expendable.  They would probably be among her weakest forces.

The party knows none of this.  They wade through her minions with varying success, depending on the party and whether they're tactically capable.  Since the only thing they've fought in this campaign are a bunch of kobalds, it's probable the fighters and spellcasters are still 1st level.  Perhaps the cleric is 2nd, and probably the thief if there is one.  Still, it's reasonable to expect the players should win ... and they might gain enough experience from the fight for one or two of them to ascend a level.

[I don't use the dumbfuckery of studying for extra levels, because it adds nothing to the game ... it's a bogus arbitrary penalty for success of play, without meaningful opportunity for roleplay or player improvement — how exactly do you improve your "skill" at navigating the game mechanic of paying an NPC to push you up a level?  It has as much relevance to PLAY as being told that because you lost a piece in chess, you have to get out of your chair and kowtow once to your opponent to express your reverence for his or her skill]

So, the minions are dead, the Witch knows more about the party and the party ... well, what does the party know?

A., that creatures came out of the dark and attacked them without provocation.  This happens so often in D&D that it's doubtful the party will give it a moment's reflection.  I'd be very surprised if someone in the party remarked, "Why do you suppose they attacked us?"  The almost certain reply, not from the DM, would be, "They're probably evil."  Which conveniently solves all motivations, though in fact it's exactly the sort of in-game meta-thinking that gets parties killed.  More on this in a moment.

B., that it's probably safe to keep going.  The party doesn't know these are minions; they don't know anything!  As far as the party knows, or cares, these 15 repulsive creatures have been wandering mindlessly around the dungeon for 25 years, while just happening to remain together all this time and clearly lacking any connection whatsoever to anything.  I've been running fairly smart parties for more than 40 years and I have yet to have a party that gives any serious thought to the simple question, "What do these creatures do here when we're not around?"

Mostly, the only party concern is how much damage did they take and whether they can fight another battle — just like this one — with success.  It never seems to occur that the next fight may have 10 times as many creatures, because that's how armies work.  First, you stumble across a picket, then you're swamped by 150 soldiers.

But 40 years of mawkish D&D has trained any of those thoughts completely out of the players' heads.  Monsters exist for players to kill.  These 15 were right here because that's how the adventure's designed.  "It's not like the DM's just gonna kill us."

As a DM, however, we're bound to none of these assumptions, not by any rule.  As it happens, I'm not going to slaughter the party with 150 mooks in the next five minutes ... since, obviously, 150 make a lot more noise than 15.  But I could, and I'd be legitimately in my rights to play it that way.  I could easily say to the party, "You hear the sound of another group coming ... only this one is much, much louder" ... and see if they'd scatter or stupidly wait for the army to arrive.

MY responsibility in the "game," which isn't real life, is to ensure that the players have a reasonable chance of deciding ahead of time if this is a good time to fight or not.  A "reasonable chance" means providing them just enough intel to give them reason to question what would be the best action right now.  Such as,

DM: You hear a bunch of something shambling and squirgeling towards you from around the bend ahead.

Player: Squirgeling?

DM: Sounds like wet, fleshy masses slapping on stone.

Player: Oh.  How many masses are we talking about?

DM: You can't tell.  More than ten.  Probably not more than twenty.

There.  I've done my diligence.  It does not matter if the dungeon has been scripted out three months ago; it does not matter that the players haven't chosen a passage or a doorway.  The mooks are squirgeling towards the players because a higher intelligence has sent them, and they know every inch of these caverns.  Perhaps this is the third time the mooks have tried to find the players and attack them, only it just hasn't happened.  What matters is the players hear them coming.  This gives a chance for the players to run ... or ready themselves to fight.

This is moment at which the meaningful game choice is made.  Commit to what's coming or run.

'Course, players hate, hate, hate running from things they haven't seen.  And that is the sort of posturing pretense to heroism that gets parties killed.  Though of course, that's not our problem as DM.

We warned them.  We sent a simple reconnaissance mook-troop to test the party's strength.  And having revealed their strength to the Witch (without the slightest notion in their heads that she watched the whole thing), when we send the next group against the party, we don't have to "play dumb" about what player character does what in a fight.  The Witch can send a smarter, stronger, better prepared contingent, enriched with intel, to snuff out the party properly.

Which we'll come to.  First we have to discuss point (a) from the previous post, in which the players stumble across unintelligent creatures that just happen to live here.