Same idea as the previous one, getting right into the new part:

Spoilers for the entire game

Caves normal enemies:

Vampiric bats serve as a sort of middle-ground between fodder enemy and consistent DPS check, they have the same movement speed based tricks as a sewer crab except they also heal on hit if they deal damage at all, meaning they require the player to have some consistent or powerful enough source of damage to reliably kill them before they win a battle of attrition against them. As a general reward (beyond just staying alive and general progression) it can drop health potions reliably, being the caves' main source of them.

For veterans, vampire bats are still challenging enough to keep the game interesting but their counters (generally having up to date equipment for the occasion, or some niche-er source of dispatching enemies) prove to be enough to keep them from being as annoying as, say, a crab while you've had no new equipment since the start of the sewers - you have plenty more options now.

Gnoll Brutes serve as a test for newer players after they were taught about last-resort abilities by skeletons, and even if those failed to properly teach the player in time they can always use the inspect button while they're berserking to understand exactly what's going on.

Despite the simplicity of dealing with brutes after they begin berserking, they can still prove especially dangerous even to veterans if the player ever runs out of escape options/gets cornered as the brute is still mobile, as by that point it's just down to either a massive hit getting taken (for the player or the brute) that often results in death, or a few decently hard evasion checks that realistically should never be trusted in the first place.

Gnoll shamans serve as the resident "ranged options check" of the caves, while also being a soft tutorial for the dwarf warlock's debuff. Instead of the warlock's heavy penalty (degrading any equipment that has high upgrades, which could have been a crutch for newer players encountering it and crippling it heavily) they simply debuff a stat indicated way beforehand by the color of their masks (red for attack, easy enough since red is a color often associated with hostility and they would debuff that, blue for defense with similar reasoning, and purple for... the hexed status effect, i think? it's a looser connection to be sure, but does anyone know why purple if not for the hexed status?)

For all players the gnoll shaman complicates interactions with other, otherwise simply countered enemies (sniping you while you outrun an enraged brute or forcing you to take a few hits from a bat in order to use it as a temporary shield for its blasts, for instance - a similar case to DM-100s.)

This enemy also uniquely rewards the player with wands, though at a rate that specifically discourages farming them. The wands given make gnoll shamans worth actively engaging if seen, just for that chance at an extra - possibly invaluable in the long run - piece of equipment.

Cave spinners act as a sort of next-step for prison guards, instead of blindly running in and keeping you in melee range, they deliberately restrict you still - except they poison you once, then run away in order for the full poison damage to take effect. This cycle keeps the player very motivated to think of ways to break past the spinner's web and avoid any direct confrontation with it, the web blocking any projectiles (or at least the 1st one if it isn't a bow shot, as bow shots don't break webs at all) prevents the otherwise simple solution of just spamming it with ranged attacks before it approaches too close, as you need to spend a turn to even enable that idea. Despite this, the spinner still has a few subtle flaws the player can exploit, like the way it aims it's web or the fact webs are very much flammable, or that every item that hits a web destroys it.

Overall, cave spinners still prove to be a massive challenge for even veterans because of their complexity. Especially notable is the projecting cave spinner, since they give you much less time to counter them and can often jump into the room, hit you once, then leave until the poison they inflicted wears off.

edit: (post rework, projecting cave spinners still do pose a threat but are much more reasonable to fight, keep alert nonetheless! A new possible threat could be antimagic ones, since the only thing that can pierce a web in 1 turn is a disintegration beam; magic (or fire, but guess what a fireblast wand is)

DM-200s introduce the player to 3 concepts, each one also forshadowing the boss: -Enemies can be large, making them unable to fit through gaps that are small but often being an indicator of massive power. -Large enemies will have some sort of coverage for ranged attacks, even if they cannot move themselves to where the attack will hit them from (gas venting, this also discourages hiding in a doorway they can't reach and hitting them with any extra-reach weapons since the gas reaches a bit further than the DM can even see and takes a short while to dissipate, making the entire method tedious - your satiety being a timer that inherently punishes tasks that take unnecessarily long. -Large enemies will often have very strong melee attack and defense to further compensate for their size having caused issues, making direct melee combat with little forethought still a very harshly punished strategy.

Notably, these enemies also foreshadow the Giant champion type for the reasons above. These can also combine into a giant-championed naturally large enemy, providing such a challenge to defeat that, once again, the player - even if they're a veteran - is forced to seriously contemplate the idea of simply avoiding it or sneaking past to loot the room it's in, then leaving that room alone for the rest of the run.

Caves variants:

Armored brutes complicate the process of dealing with enraged brutes by lasting much longer compared to their unarmored brethren. This means that, if left alone after getting enraged, the armored brutr could potentially *re-enter the room the player is in and pose a threat again, despite already having been brought to 0 health beforehand. This encourages the player to still try to keep dealing damage to the brute in order to expedite the process significantly instead of letting a walking threat stay alive. In exchange for this, armored brutes drop a relatively strong armor for the caves and guarantee the player has at least a little extra equipment to keep themselves going.

DM-201 continue the idea of a strong but mobility-challenged behemoth a bit too extremely; they cannot move and can be entirely avoided if deemed too much of a threat - so long as you leave their 3x3 melee range in peace - but continue to offer the reward of an extra cursed metal shard if defeated (boss drop alchemy items are among the strongest, so this is both a reminder to new players that alchemy matters and a gift to veterans)

my only issue with 201s would be how difficult it was for their visual distinction from 200s to catch on - at least for me, if it was for you as well then please say so because i don't know if this was just a "me" problem.

Caves Miniboss(?):

Vampiric bat (but you have a pickaxe) can genuinely pose more of a threat than the average enemy because instead of whatever else you've been using, you have to use a mediocre tier 2 melee weapon with effectively no strength-buffed damage for the region. This makes it a test of your armor or other damage reduction tactics, to ensure you didn't somehow make it all the way to the blacksmith with a purely unga-bunga fighting style.

Caves Boss:

The DM-300 takes what you've learned from 100/200/201 (inorganic so immune to tox gas/bleeding, large enemy qualities) and emphasizes them greatly, having not only constant vents of toxic gas with massive range, but a (well-foreshadowed) rockfall that further allows it to catch up with the player should they outrun it and make a mistake in the process.

The pylons serve as a forced break so that the player both has something extra to do as opposed to "kite the big man until he falls over" and as an added challenge since 1, you're being chased by an overloaded DM-300 and 2, the pylons force you to keep running around while hitting them in order to dodge their electricity. This is further enforced by their taken damage cap which both prevents new players from accidentally not learning to dodge the shocks, then getting taken by surprise once they try to wail on it without dodging the next time, and prevents veterans from flying straight past the challenge posed by each pylon. (also a slight foreshadow to a certain miniboss in the demon halls, by the way.)

Similarly to the DM-201 issue, i actually think that the electricity for the pylon segments might be too little of a foreshadow, both from personal experience and having seen a few people ask about it in the past, unaware/unsure what the direction meant.

City normal enemies:

Dwarven ghouls serve as a more extreme case of vampiric bats, being a mullti-target DPS check while having 2 built-in failsafes if the player has enough defense to tank them but not enough offense to properly dispatch multiple in the span of a few turns: 1 - they get back up at very low health every time 2 - they take increasingly longer every time they get back up, meaning you can eventually whittle down even a horde using high defense and low dps - although this will still discourage high defense strats in the future (for good reason, FiMA prep) in favor of builds that can speedily dispatch or otherwise deal with every threat they come across.

As well as this, the ghouls also wander around in pairs to keep the gimmick going always. These pairs are tight-knit and subtly encourage alchemy even further, since enhanced bombs tend to be unlocked in the alchemy book by the time the player reaches the city for the first time, and they tend to deal with groups of enemies spectacularly. Some potions can also do the job just fine as well, like toxic gas or dragon's breath.

A particularly dangerous type of ghoul would have to be blazing for a very similar reason to flies.

edit: (this is still true after the blazing nerf, but i would say the new biggest threat is likely antimagic or giant ghouls, since they can tank most aoe/most single target dps options much better than their cohorts and can distract you while backup arrives (leading to the player getting overwhelmed and dying)

Elementals (fire and frost) serve as one of the 2 resident magic attackers of the city, however elementals are much more mixed in their approach; they fire off debuffs that will - in some way - (slowing you down increasingly with chill, burning you to reduce the health amount you can work with over time) make the player want to speed up the encounter and kill the elemental quicker, while still approaching them after firing off that 1 bolt.

Notably with fire and frost elementals, their most obvious counters are also a way to keep the player feeling like they solved the puzzle instead of the game doing it for them; nobody ever directly tells the player to freeze a fire elemental outside of the newborn in the prisons, or ignite a frost elemental ever. Despite this, they have these weaknesses and players who exploit them are greatly rewarded with having just skipped a fight against an otherwise moderately powerful opponent.

Dwarven monks further punish the idea of running into combat headfirst with their unexpectedly high melee damage and speed, as well as their reusable focus. Their focus also discourages running for doors and sneak attacks (or in general) since it renews much faster if they're moving, which effectively resets the encounter's toll on them by granting another free hit to tank.

Veterans find plenty of ways to deal with these melee-range menaces, like how they simply cannot parry magic or elemental effects or are just as vulnerable to corruption as any other enemy (meaning they serve a greater purpose for you if corrupted as opposed to most other enemies due to their mindless power)

Overall, monks serve as the greatest punishment for unreliable noob-trap-y strategies, and would be a great forced learning moment for any players that only relied on those for the entire run. In exchange for this massive challenge, they get rewarded with the ability to effectively turn back the clock on their satiety timer (rations drop frequently)

Dwarven warlocks serve as a test for the tutorial you get given by gnoll shamans and DM-100s, with the aforementioned downgrade status. This discourages running towards the chapter's resident "magic blasts zoner" the most, as it cripples what you would be using to both deal with it's surprisingly decent melee damage capability and hit it back. This also heavily punishes ranged vs. ranged for a similar reason, meaning most often your best bet with them is to use the terrain of dwarven city to your advantage and lure them into melee range without having ever fired a single bolt.

Golems serve as the resident large enemy, keeping you inside their range if you try to run away or hide as opposed to simply hitting you with a weaker gas-based effect. This further emphasizes the general design of large-type enemies and has most of the same implications as a DM-200.

Notably, Golems have the ability to teleport themselves across rooms as well, as a substitute for natural hallway-based movement. This can both help and harm the player as they can awaken a golem, then make it leave the room by running back out - leaving the room open in exchange for having just activated a teleporting menace.

City variants:

Shock elementals serve as a slight juxtaposition to the standard 2, as they have no elemental counter and hit enemies harder generally in water. they are also uniquely one of the 2 enemies that can reliably counter an ally-centric build, since they deal chaining damage with every melee hit if they are hitting more than 1 target. This ensures that just about every build has some counter while also providing a great reward on death, frequently dropping a scroll of recharging (wands are incredibly useful and reliable, faster recharge is always a bonus!)

Chaos elementals generally pose a random amount of risk since they relybon cursed wand effects as their specialty, however they do this very well and are arguably a subtle hint at cursed wand builds being slightly viable, due to all the useful things cursed wands can do for the user (albeit with massive risks on every zap if the user isn't properly equipped to handle them)

even if they're immediately dispatched with total ease, chaos elementals serve as the 1 enemy that can reliably drop scrolls of transmutation, which some newer players might never have even seen until the moment they slay one. This in itself is reason enough to appreciate their existence.

Elder monks are monks, but they have unencumbered spirit and +16 gloves. They drop an even better food reward but i lack any serious way to add to their analysis besides a generic "harder enemy variant, better reward".

City miniboss:

ERROR: NOT FOUND. REFER TO PROTOCOL H FOR INSTRUCTIONS.

City Boss:

Dwarf King poses as a mixture of tutorial and boss, his phases' general structure acts as a tutorial for how Yog fights, with phase 1 encouraging you to hit the big bad (yog without any fists active), phase 2 requiring you to hit the summoned enemies instead in order to return to damaging the big bad (yog's fists being active) and phase 3 showing that you can return to damaging the big bad after phase 2.

DK also expands the player's arsenal with their armor ability on death, as well as a quick warning about what lies below.

Misc. enemy/variants

Animated statues serve as both a mini-tutorial on the gimmicks of certain weapons or enchants, and a way to always make sure the player has some way to arm themselves at various points of the game. These statues seem very threatening in direct melee combat for good reason, however their lack of any proper high defense or gimmicks besides simply having weapons makes them exposed to plenty of things like standard ranged attacks and zoning, elemental damage and falling into pits.

Summoned guardians serve as a "punishment" for triggering alarm traps and have large amounts of bulk, although only ever have a +0 unenchanted weapon. The best way to handle them would vary depending on your build but they carry the same weaknesses as a standard animated statue.

Wait...

WHAT DO YOU MEAN YOU GAVE THE STATUE ARMOR?

in all seriousness, armored statues are in a similar situation with normal ones as elder monks are with their younger counterparts. They pose a much greater risk, and serve a much greater reward in return.

Lastly, a bit of a reminder: You do not have plot armor.

Be careful with how you approach any threat in the dungeon. A grim-weaponed statue could be your ticket out of the sewers, or if handled poorly it could result in your run ending before you ever made it out of said sewers.