Segmented Creatures (3.5e Other)
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I have, in other places, written on the concept of "economy of actions." In the context of this article, it's important to know that the concept refers to how equal-on-paper encounters can be thrown out of whack in a hurry when one side gets many more actions than the other.
For instance, a 10th-level Cleric is on paper an extremely strong challenge to a 6th-level PC party (as in, the CR system says there's a 50/50 chance of TPK), but it rarely works out this way in practice--primarily because no matter how well the Cleric plays his hand, he still only gets one turn per round and one pool of hit points and resources to work with, so PCs can overwhelm him pretty quickly. Thus, a truly balanced and challenging encounter is more often a match-up of PCs against a squad of enemies of nearly the same level, and not a five-on-one gang-bang.
This is pretty limiting in terms of the sorts of endings you can put on your stories. Big Bads are typically the most conceptually impressive encounter, and sometimes a single massive bad guy is the most logical or thematic choice. Unfortunately, the game doesn't usually reward that choice unless you increase the Big Bad's level far beyond your players' ability to handle.
Enter the idea of the Segmented Creature: one creature that is treated as several separate ones (for purposes of targeting, HP, actions, and so on) by separating it into disparate segments. This allows for one creature to pose a proper challenge when heavily outnumbered, and allows you to replicate some interesting concepts that weren't necessarily available before. With this, you can finally use one really impressive creature to lend your climax an appropriately epic scope, and still have it get enough actions to not be overwhelmed by the PCs.
The concept is kind of complicated, so I'll do my best to explain by giving an example of a single Big Bad and applying this process to it.
For our example, we're going to use Sparky, a retriever. It's a really big construct with only a few extra abilities and no feats or skills. This means it's fairly easy to convert, but with enough abilities for us to see exactly what's being put where and why.
 Step 1: Identify Creature Segments
The number and identification of segments will vary based on your creature's anatomy and the difficulty level you desire (more segments = higher difficulty). Very broadly, your creature should have a Head and a Body; limbs bearing major modes of attack, movement types, or primary abilities should typically receive their own segments. In other cases, Head and Body may be close enough in function (compared to other parts and your desired difficulty level) to be taken as a single segment.
 The Example: Sparky, Step 1
For this example, Sparky's head has several abilities that could theoretically go to it specifically, so we'll make the head and body distinct segments. It has four separate claw attacks, so we'll likewise make those each a separate segment. We could make Legs and Body distinct segments as well (if you wanted to leave PCs the option, for instance, of immobilizing the creature without killing it), but since neither has anything particularly interesting to do without the other, we'll leave them one section. That leaves us with the following list: Head, Body, and Arms 1-4.
 Step 2: Calculate Base Statistics
In order to avoid over-complicating things, we try to unify as many of the creature's statistics as possible across segments. Initiative, AC, BAB, grapple mod, space/reach, resistances/immunities, damage reduction, spell resistance, saving throws, ability scores, feats, and skills should all generally stay the same for each segment. You can mix-and-match these as appropriate for your creature, but remember that the more of these are the same, the easier the creature will be to use.
 The Example: Sparky, Step 2
Sparky's not too complicated when it comes to his stats and such, so everything listed above can stay the same for every segment. If you wanted to get creative, you could give a different Reach to his claws than to his bite, but for our purposes we'll leave these be.
 Step 3: Apply HP Modifiers
As part of this conversion process, a Segmented Creature typically winds up with many more hit points than its one-piece equivalent. This step will depend largely on physiology, but you can apply some basic rules of thumb:
- The creature's largest segment (usually Body) usually gets HP equal to the base creature's full max HP.
- Other major segments (such as Head and limbs bearing primary attacks) typically get 1/2 HP.
- Other segments with minor abilities or that are physiologically more fragile (tentacles, wings, eye-stalks) each get 1/4 to 1/3 HP.
 The Example: Sparky, Step 3
Our base creature typically has 135 hp, so we'll start by giving Sparky's Body that number. His Head is likewise a pretty major component, so we'll give it half that number, or 68 hp. We could go either way with his Arms, but I think for this example we'll say they're minor components and give them 1/3 the full tally: 42 hp each.
 Step 4: Assign Attacks and Special Abilities to Segments
This tends to be pretty simple, since we're already pretty much divvying segments based on special abilities. Some quick notes, however:
- The creature's Head is usually the seat of any spell-like abilities it has. If the creature has actual spellcasting, it is also usually in the Head, but the removal of Arms may remove the ability to use somatic components.
- The Head is also usually the seat of sensory abilities, but this can vary. Tremorsense, for instance, is usually attached to either Legs or Body (or whatever body part is on the ground). Blindsense may represent feelers or other skin-based sensory receptors, or even some sort of internal gyroscopic organ. Use your own discretion.
- Any healing abilities (such as regeneration, fast healing, or just curative spell-like abilities) are usually granted to the Body. Such abilities actually work simultaneously on all segments (for instance, a troll would regenerate 5 points of damage per round to each segments), but destroying the Body ends this effect for all parts (see Step 5).
- Movement abilities can vary a little bit. Base land speed is usually given to Body (or Legs, if they're separate). Flight is usually given to a Wings segment, allowing you to bring a flying creature down to your level by clipping its wings. Swim is usually given to Tail, Body, or Legs as appropriate. Burrow is usually given to Arms.
- Some segments may have the ability to protect other segments, such as Arms being able to curl in and protect the Head and Body. These segments should get the following two abilities:
Cover Guard (Ex): So long as at least one (chosen body part) is functional, this creature's Body and Head gain the benefits of evasion.
Sacrifice (Ex): As an immediate action, this creature can choose to apply the effects of an attack to (chosen body part) in place of another body part.
 The Example: Sparky, Step 4
Sparky's extraneous parts, the four Arms, are defined by their attacks, which makes this pretty easy: the four Arms each get a claw attack and the ability to protect the Head and Body.
The Head, meanwhile, gets a bite attack and the base ability that relies that rely on it (improved grab), as well as the eye rays. None of the sensory abilities look like they should logically go anywhere else, so find target and the visual powers all go to the Head as well.
Movement and fast healing are given to the Body.
 Step 5: Determine Effects of Segment Loss
In this step, you get to try and apply logic to DnD. Oh, won't this be fun!
First you need to decide, based on your creature's physiology, what parts of it are vital and what are not, as this will determine how your creature dies. Some creatures with unusual physiologies, such as a gibbering mouther, may not die until every last piece is torn asunder. Others, such as a vampire, may die once their Head alone reaches -10. For creatures with unusual but not totally alien physiology, a requirement of Head or Body to function is probably good (this prevents one lucky head-shot or death effect from killing your entire encounter, while still imposing significant penalties--see below).
Next, determine what penalties your creature takes for losing a particular segment. Segments with attacks will have these attacks become unavailable, for instance. Segments that provide movement, such as Wings or Legs, will have speed slowed or eliminated (a creature with eight Legs, for instance, might lose 5 feet of speed for every one severed, while a creature with only two Wings might lose flight entirely if one gets ripped off). Segments providing sensory abilities will see those go away, possibly rendering the creature blind, deaf, or more.
If you decide that the Head is not necessarily vital to life in and of itself, significant penalties should still be assigned to its demise. Typically, above and beyond losing most sensory and spell-like abilities, a creature whose head has been irreparably damaged will be confused (or some similar effect).
Some notes on segment death:
- Death effects must target a particular segment, and immediately reduce it to -10 hit points, but do not affect other segments.
- A segment reduced to negative hit points is disabled, and may be treated with the standard rules for death and dying. It is not irreparably disabled until reduced to -10 hit points, and if healed will resume full functionality.
- You can consider any segment that is reduced to -10 hit points as having been severed from the rest of the creature.
 The Example: Sparky, Step 5
In this case, since Sparky's a construct with Int -- (and thus isn't reliant on a brain or head to live), I'm going to say both Head and Body have to go down for him to die. Demise of the Head alone, as suggested, leads to the blind and confused conditions, as well as the loss of visual abilities (darkvision and low-light vision) and attacks.
Loss of the Body means that Sparky's going to have a hard time moving--having several other limbs means he can crawl along, so his speed isn't removed completely, but speed will be reduced to 5 feet/round. This will also kill his fast healing.
The demise of one of Sparky's Arms simply eliminates the associated attack on each limb.
Some last-minute general notes on how other abilities interact with this "template":
- Area-of-effect abilities, such as fireball, affect all parts of a segmented creature. To save time, roll one save for the creature as a whole, then apply effects to each segment. (Note that some segments will take such effects differently than others--if certain parts have the cover guard ability mentioned above, for instance, some parts will have evasion while others do not.)
- Certain status effects and spells bestowing such will only affect on certain segments. Blindness, for example, will only affect a segment with sensory capabilities attached. Other effects, such as paralysis, can affect any particular segment with equal effect.
- Because each segment is treated as its own creature, a segment can initiate a grapple while the rest of the creature is free to act normally. This makes segmented creatures awesome grapplers.
That said, by this point you should have a completed creature resembling the stat-block listed below. You should likewise be seeing that, even though we selected a totally unintelligent creature with few special abilities and a straight-forward style, adding this "template" has given it more options and tactical depth. This is a more formidable adversary for a full team of opponents, requiring teamwork and forethought to defeat--one could easily imagine Sparky here showing up at the climax of an adventure!
 Sparky, Segmented Demon (Retriever) — CR 11
- Segments Head, Body, 4 Arms
- Base Hit Points 135 (10 HD); Hit Point Multipliers Head x1/2, Body x1, Arms x1/3
- Init +3
- Languages Sparky understands Abyssal, but does not speak.
- AC 21 (-2 size, +3 Dex, +10 natural), touch 11, flat-footed 18
- Immune Death effects, mind-affecting effects, necromancy, paralysis, poison, sleep, stunning
- Fort +3, Ref +6, Will +3
- Space/Reach 15 ft./10 ft.
- Base Atk/Grp +7/+25
- Abilities Str 31, Dex 17, Con —, Int —, Wis 11, Cha 1
- Feats —
- Skills —
- Special Sparky dies if both the Head and Body are reduced to 0 hit points.
 Sparky - Head
- HP 68
- Senses Listen +0, Spot +0; darkvision 60 ft., low-light vision
- Melee +15 bite (1d8+5)
- SA eye rays, find target, improved grab
- Eye Rays (Su) Sparky's eyes can produce four different magical rays with a range of 100 feet. Each round, it can fire one ray as a free action. A particular ray is usable only once every 4 rounds. Sparky can fire an eye ray in the same round that it makes physical attacks. The save DC for all rays is 18. The save DC is Dexterity-based. The four eye effects are fire (12d6 points of fire damage to the target, Reflex half), cold (12d6 points of cold damage to the target, Reflex half), electricity: (12d6 points of electricity damage to the target, Reflex half), and petrification (target must succeed on a Fortitude save or turn to stone permanently).
- Find Target (Sp): When ordered to find an item or a creature, Sparky does so unerringly, as though guided by discern location.
- Improved Grab (Ex) To use this ability, Sparky must hit with its bite attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold and grips the opponent fast in its mouth.
- Special If the Head is reduced to 0 hit points, Sparky loses darkvision and low-light vision, and is both blind and confused. He also loses his bite attack, improved grab, find target, and his eye rays.
 Sparky - Body
- HP 135
- Speed 50 ft. (10 squares)
- SQ fast healing 5
- Special If the body is reduced to 0 hit points, all segments lose the benefit of fast healing, and speed is reduced to 5 ft (1 square).
 Sparky - Arms (4)
- HP 42
- Melee +15 claw (2d6+10)
- SA cover guard, sacrifice
- Cover Guard (Ex) So long as at least one Arm is functional, Sparky's Head and Body gain the benefits of evasion.
- Sacrifice (Ex) As an immediate action, Sparky can choose to apply the effects of an attack to one of his Arms in place of another body part.
- Special If an Arm is reduced to 0 hit points, Sparky can no longer use it to attack, nor use any of its special abilities.