Really, the issue isn’t that the zodar is underpowered. I mean, it is, but that’s not the problem. The problem is that the zodar is boring. It doesn’t fit into any setting, it doesn’t provide interesting hooks to the players, it doesn’t cause fun battles, it doesn’t let characters show off their powers, its own powers either don’t make sense or are used so rarely they might as well not exist, and its presence doesn’t lead to anything. Its low power level is just the cherry on the sundae. To make a worthwhile zodar we have to solve both problems at once.
I really like the idea that each zodar is a tool or highly-limited avatar of a powerful, forgotten entity. It means there isn’t one zodar, but several, possibly with different purposes and powers. It gives us some framework for giving them new abilities beyond turning their current abilities up to eleven and it doesn’t conflict with anything they’re already doing. But we don’t want to define some list of relevant personalities because they may vary from setting to setting and we want the zodar to be universal. For this reason we can’t use existing deities or anything like the vestiges from the 3.5E Tome of Magic, and I want to avoid using domains because I don’t want them to be tied to divine energies. What we need is a list of vague and mysterious forces, acting for reasons the characters and players might not entirely understand. We don’t need to name these forces, we just need ideas for them to give power and influence to zodars.
Oh, wait, that’s almost exactly the text of the opening paragraph for witch patrons. That’s perfect. Patrons are very intentionally not defined; a patron that grants healing powers could be an ancient positive energy elemental, or the primal energy of the planet itself, or even a god of healing. The source isn’t important to defining the monster’s stats, only their effects. A DM is free to reskin a healing zodar as an avatar of Sarenrae or a manifestation of the universe intended to fight against undead or the first wave of a malevolent outsider trying to force the growth of life in a world that can’t handle it. The story specifics are only important in that they give the DM a seed to fit zodars into their setting, which is already more than they had.
We’ll be focusing on what this does for the zodar’s stats, using the twelve patron types in the Advanced Player’s Guide. But that can’t be the only thing we do. The creature is still underwhelming, and we have to bring it up to an expected power level for Pathfinder and late 3E D&D. Part of this is a from-the-ground-up rebuild of the creature to fit with the changes to the construct type. I really, really want to give it an Intelligence score because its mindlessness actively conflicts with everything else about the creature, but let’s assume that’s just part of its charm and we can’t do anything about it. This means it can’t meaningfully recognize and react to situations, so giving it a slew of spell-like abilities won’t serve us in any way. We have to make its powers mostly passive or automatic. We also have to address some of the meaningless slog players face in fighting it and bring its offense up to the level where it proves a worthwhile threat.
Let’s start with the existing zodar powers and see if we can’t do anything about them:
Invulnerability (Ex): A zodar is impervious to all attacks except those from bludgeoning weapons, and the enhancement bonus (if any) of such a weapon is disregarded when determining the result of the attack.
Here’s the biggest problem and the one that leads to the most frustration. If you don’t have the silver bullet to kill a zodar, too bad. If you do have it, you’re still taking forever to whittle away at it while the rest of the party stands around. And why are zodars vulnerable to bludgeoning damage? We don’t know. There’s no purpose to this ability. But it’s also the zodar’s main source of defense, so we can’t just toss it. We have to make it interesting.
What if it was variable? That is, one zodar is resistant to everything but bludgeoning, and another everything but slashing, and another everything but acid, and so on. If you want to make a full-bore puzzle boss you could even make a zodar vulnerable only to falling damage or rock salt. Also, let’s get rid of its total immunity. I’m much happier with damage reduction and regeneration; the regeneration means only one party member needs the silver bullet to disable the region so the other players can contribute, and the DR keeps it alive against players who try to hit it with a truck instead of going for the vulnerability. It can’t actually be regeneration because that’s only available to creatures with a Constitution score, so we have to spoof it somehow. We can also give it some sort of immunity to death unless its vulnerability was relevant in its defeat. That gives it a Terminator-like implacability, letting one zodar meet the party several times until they can put it down once and for all.
Burst of Strength (Ex): Three times per day, a zodar can double its Strength to 50 for 1 round (Str bonus +20).
This is the zodar’s only real offensive power and it’s quite terrible. A +13 bonus to attack and damage is great, but by the time they fight a CR 16 monster most players with Power Attack are dealing +12 damage any time they want, and there’s no difference between barely hitting a target and beating its AC by fifteen. And why only three rounds per day? This works as a sudden spike to put a bit of fear into the players, but it plays itself out rapidly.
To address this, consider where the burst of strength comes from. What if it’s channeling the power of its patron? Most of the time, the zodar is a mindless puppet half-remembering its creator’s will. For some rounds per day, it become a direct conduit to that patron’s power, gaining great strength via a temporary connection. Given that view, it really should grow in much more than carrying capacity. It should be faster, smarter, stronger, everything you expect from the avatar of an ancient power. It can even transform physically as its patron manifests in this world. We’ll need a total rewrite of the ability to do that, but we’ll keep with the spirit of the short-lived burst of power.
Wish (Su): Once per year, a zodar can alter reality as if it had just cast a wish spell as a sorcerer of the same level as its Hit Dice. None has ever been known to actually use this ability more than once in a century. Even when the effect of the wish is of great importance, it is likely to be subtle and largely unrecognized as the work of the zodar.
This can stay, but we can’t have a mindless creature making clever, subtle wishes. We’ll restrict this power only to times when the zodar is channelling its patron.
Constrict (Ex): When fighting barehanded, a zodar seldom punches. Instead it attempts to grapple normally. If the grapple attempt succeeds, then the zodar constricts its foe, dealing 1d6+7 points of damage each round the hold is maintained.
I’m wary of anything that leads to grappling, especially when that grapple does significantly less damage than straight-up punching. It doesn’t add anything to the zodar, but if we are going to keep it we need to bump up the damage to make it worthwhile.
Updating the zodar to Pathfinder rules is trivial and boring, so we won’t discuss it. Instead I want to touch on the hard part, coming up with a list of new abilities based on the patrons. The patrons have some issues when we try to apply them to our zodar. For one, they’re definitely designed for a spellcaster. The elements patron doesn’t do much besides energy damage, and endurance isn’t helpful for a creature immune to fatigue. Also, there’s a lot of overlap in patrons. Deception and trickery are two separate patrons for reasons you couldn’t pay me to understand, and a lot of what I’ve considered for endurance, strength, and transformation could have conceivably fit under each other. Third, as we said, our abilities have to be passive or automatic. That’s great for patrons like water, but not plague. We’ll have to get very creative to make those meaningful.
We can partially address this by combining our two biggest powers: the burst of strength and the patrons. Instead of just making the zodar stronger, let’s increase its defenses and intelligence too, until it’s smart enough to use active abilities and tough enough to survive until it can. Now we don’t need everything to be passive, just some of it, and during the zodar’s modified burst of strength it can act with purpose. And as long as it has Intelligence, it now qualifies for skills and feats. Technically it can swap out whatever skills and feats it wants when its Intelligence balloons, but that’s a lot of work for a DM to do on the fly, so let’s hard-code it by patron.
Here’s what we have:
ZODAR
XP 76,800
Any alignment medium construct
Init +4; Senses darkvision 60 ft., Perception +3
— DEFENSE —
AC 31 36, touch 14 19, flat-footed 27 32 (+4 Dex, +17 natural, +5 deflection)
hp 135 (21d10+20); fast healing 25 (see invulnerability)
Fort +7, Ref +11, Will +10
DR 25/— (see invulnerability); Immune construct traits
— OFFENSE —
Speed 60 ft.
Melee 2 slams +28 (2d6+7 plus grab) +41 (2d6+20 plus grab)
Special Attacks constrict (2d6+10) (2d6+30)
Spell-Like Abilities (CL 21st)
3/day — hydraulic torrent
— STATISTICS —
Str 25 50, Dex 18, Con —, Int — 20, Wis 16, Cha 10
Base Atk +21; CMB +28 +42; CMD 41 54
Feats None Dodge, Mobility, Spring Attack
Skills Acrobatics +4 (+16 when jumping), Knowledge (geography) +26, Swim +15 +49
SQ patron, manifest
— ECOLOGY —
Environment any land
Organization solitary
Treasure magic items only
— SPECIAL ABILITIES —
Manifest (Ex) A zodar’s patron occasionally feels the need to work through it directly. As a swift action, the zodar’s patron can manifest in the zodar’s body. It can spend up to 1 round manifesting for every 3 Hit Dice the zodar possesses. While manifesting, the zodar’s Strength increases to 50 and it gains a +5 defection bonus to AC. A manifesting zodar has an Intelligence score of 20. The Intelligence score is considered a temporary bonus, but the zodar gains feats and skill ranks equal to its Hit Dice in two skills. These skills and feats are determined by its patron. All changes are included above in red. It can end its manifestation as a free action, but it must wait at least one minute before manifesting again.
A zodar can manifest for longer than usual for critical tasks. For every round it manifests beyond its limit, the zodar takes 25 damage. This damage counts as a weakness for the purposes of its invulnerability, which negates its fast healing. A zodar can die from manifesting too long.
Invulnerability (Ex) Zodars are unnaturally difficult to kill. A zodar heals 25 damage each round and has DR 25/— against all sources of damage. Reducing a zodar to 0 hit points stuns it for one minute, after which it regains all lost hit points. Each zodar has a specific weakness that negates its fast healing for one round and ignores its damage reduction. This weakness may be a type of damage, like slashing or acid, or it may be a material or situation, like mithral, falling, or the light of the full moon. If a zodar is reduced to 0 hit points within one round of taking damage from or experiencing its weakness, it is killed.
PATRONS
A zodar is commanded and powered by an unknown force, and some of its abilities demonstrate its controller’s power. Each zodar has a single patron that grants it abilities according to its theme. Often a zodar’s armor subtly hint at its patron, and though mindless it acts roughly in keeping with its patron’s intentional and alignment.
If a zodar has a spell-like ability from its patron, its caster level is equal to its Hit Dice and its save DCs are Charisma-based with a +4 bonus.
Agility: The zodar has an additional +10 bonus to Acrobatics checks made to jump. When manifesting it gains a +4 bonus to Dexterity and gains an additional slam attack. Skills: Acrobatics, Climb; Feats Combat Reflexes, Improved Initiative, Run.
Animals: Animal and vermin will not attack the zodar except in self-defense. While manifesting the zodar’s slam attacks become claws and it gains a bite attack. This is a secondary natural attack that deals 1d6 points of damage. Skills: Handle Animal, Knowledge (nature); Feats Critical Focus, Multiattack, Vital Strike.
Deception: The zodar is immune to detection via divination spells. While manifesting the zodar has partial concealment. Skills: Bluff, Stealth; Feats Combat Expertise, Improved Feint, Lunge.
Elements: Select one energy type (acid, cold, electricity, fire, or sonic). Any damage of that energy type heals the zodar instead of damaging it. If the amount of healing would cause the zodar to exceed its full normal hit points, it gains any excess as temporary hit points. These temporary hit points disappear after one minute. While manifesting the zodar deals an extra 2d6 points of its chosen energy damage with a successful slam attack. Skills: Knowledge (arcana), Knowledge (planes); Feats Disruptive, Dodge, Lightning Reflexes.
Endurance: The zodar gains a +5 bonus to saving throws. While manifesting the zodar ignores any ability against which it succeeds on a saving throw, even if that ability would normally have a partial effect. Skills: Heal, Survival; Feats Critical Focus, Great Fortitude, Tiring Critical.
Plague: Undead will not attack the zodar except in self defense, and negative energy heals the zodar unless that is its weakness. While manifesting the zodar causes disease with its slam attacks as the spell contagion. It may change which disease it causes each time it manifests. Skills: Heal, Knowledge (nature); Feats Great Fortitude, Intimidating Prowess, Toughness.
Shadow: When attacked, as a free action the zodar creates an area of darkness around it as the spell. It can use the ability three times per day. While manifesting the zodar can shadow jump as the shadow dancer ability. It can jump a total of 10 feet per Hit Die per day. Skills: Sleight of Hand, Stealth; Feats Blind-Fight, Iron Will, Step Up.
Strength: The zodar’s carrying capacity is tripled as the spell ant haul. While manifesting the zodar gains an additional +10 bonus to Strength checks and to Combat Maneuver Defense when resisting a bull rush, overrun, reposition, or trip attempt. Skills: Climb, Swim; Feats Improved Sunder, Power Attack, Vital Strike.
Transformation: When the zodar takes damage from its weakness, once per day it may change its weakness to a different damage type. This change lasts for five rounds. While manifesting the zodar’s size increase to Large. Its ability scores do not change. Skills: Disguise, Escape Artist; Feats Lunge, Nimble Moves, Strike Back.
Trickery: Creatures who damage the zodar with its weakness must make a Perception check to detect that its attack dealt damage. The DC is equal to 10 + the zodar’s Hit Dice + its Charisma modifier. Only the creature who damaged the zodar may make this check. When the zodar manifests it may cast mirror image as a free action. Skills: Bluff, Disable Device; Feats Blinding Critical, Catch off-Guard, Critical Focus.
Water: The zodar has a swim speed of 60 feet and has the aquatic subtype. While manifesting it can cast hydraulic torrent as a spell-like ability three times per day. Skills: Knowledge (geography), Swim; Feats Dodge, Mobility, Spring Attack.
Wisdom: The zodar has an additional +20 bonus to Perception checks. While manifesting it has blindsense 60 ft. Skills: Perception, Sense Motive; Feats Deflect Arrows, Disruptive, Snatch Arrows.
To address the elephant in the room, yes, a CR 16 monster with +41 to attack is absurdly powerful. It’s even stronger with certain patrons, like animal. I’m okay with that because there’s a tradeoff between accuracy and damage, and there always has been. The zodar punches for 27 damage on average, so it deals 54 damage on a full attack. But a CR 16 creature is expected to deal 80 damage on average if all of its attacks hit. Even at its best a zodar barely reaches the average damage for its level, and it can only do that for a few rounds per day. I’m not concerned. If a character thinks they should hang around in melee with a manifesting zodar, that’s really the character’s fault.
I’m not happy with all of the skills and feats, but I intentionally limited myself to only the Core Rulebook. I want the zodar to be accessible. You shouldn’t need a half-dozen books to play a single monster. That did leave me with a very small number of feats since I couldn’t use anything that required a class ability, spellcasting, or equipment, and I avoided “+2 to two skills” feats because they didn’t feel interesting enough. If I open it up to the Advanced Player’s Guide, which has the witch and thus the patrons, I might be able to find something more appropriate.
I did reference two non-Core spells, ant haul and hydraulic torrent. That’s because I could find nothing else better and both spells are awesome. I’m open to suggestions.
This version of the zodar is still very specific, but it’s playable. We didn’t take away its mysterious backstory or its key traits. Instead we increased both, giving it some direction instead of a nebulous hand-wave and making it a playable puzzle instead of an exercise in frustration. We can even take this and extrapolate it to lesser zodars, a reasonable challenge for mid-level characters, or greater zodars, who fling spell-like abilities and can only be slain by specific weapons or in specific places, and there are more then thirty patrons on the SRD we can use instead of the ones above. We took a random bundle of abilities and turned it into something solid enough to use, fluid enough to change, and extensible enough to fit into several settings and plots. Basically, we changed it from what it was into a proper D&D monster.
We are not, however, giving it new art. That’s expensive.
I’m also using this chance to show off our new icon hotness. The default icons with Live GameScreen are lackluster, and we know it. 
A bad monster can be saved by a good story; the zodar is not. As I said above, they exist, and that is most of what we (characters, players, and DMs) know about them. They can talk but only do do once every fifty or sixty years, and the one sentence they say is guaranteed to be important and is understood by everybody who can hear it. Sometimes they stumble upon an adventuring party and follow them around for no discernible reason, and that’s the only way they seem to interact with PCs. They don’t guard anything, they don’t hold ancient secrets, and they don’t offer any assistance.