Behind the Screen09/26/2004

Mind the Gap
Building a Campaign Story Arc, Part 5

"All right, Eddie, Mikko is going to Climb around the edge of the cave. That water looks nasty, and besides, it's probably over my head!"

"Don't be such a wuss," Samantha said. "Arphaxad the Mighty is a halfling and he's not afraid of a little water! Of course, the fact that I can alter self into something with a swim speed doesn't hurt . . . "

"Oooh, check out the big risk-taker," Michael shot back.

"Melantha actually has a couple of ranks of Swim, so I'm game for it," Ally chimed in. "Figures I didn't prepare water walk today, and I used up my only scroll of it."

"I think this is a bad idea," David said. "I mean, come on -- we all know what happens in every fantasy and sci-fi movie or story. When you go in the water, something bad is waiting there -- a monster, some horrible disease, a whirlpool, whatever. Taking a dip is just asking for trouble! Unfortunately, my winged boots are used up for the day, so I guess it's swim along or get left behind."

"The water is calm," Eddie announced, "so getting across is not too hard. And nothing attacks you. Everyone crosses safely."

"This can't be happening," David said. "Something is fishy."

"Ally, make a Survival check for Melantha The rest of you make Spot checks."

After the checks are resolved, Eddie chuckles. "Well, none of you see anything amiss, but Melantha's knowledge of the wilds clues her in to a funny sort of numbness spreading all over her chest and legs. On taking a peek inside your chain shirt, you see that you are covered with a swarm of fat black leeches!"


Quite a satisfying reaction, and just what Eddie was looking for. If you're going to go to the trouble of creating something new, the last thing you want is a ho-hum response.

And so begins Part 5 of our Behind the Screen workshop on building campaign story arcs. Our fictional DM, Eddie, is building a theme around an ancient race of frog-folk called sivs, and we're using his process as a model for creating your own unique campaigns. Previous columns have dealt with designing monsters around a central theme, establishing the main antagonists and their servants, and adapting existing monsters by using feats, "character regions," and templates to customize them. Not everything has to tie to your main villains, though -- don't forget about the little incidental monsters that fill out the rest of a campaign. This column is about is making something new, addressing a gap in the game.

In Eddie's case, it would be a pretty boring jungle if it were simply all sivs, all the time. A jungle is supposed to be alive, so he needs to fill it. He's still working hard to create his new campaign, but decided he'd drop one of his fresh creations into his ongoing campaign to take it for a test drive. Leeches are a classic icky hazard of jungle stories and movies, so they seemed like a great filler monster to bring home the creepy jungle theme. Eddie has made his leeches a type of swarm because he noticed that most existing swarms are great for underground or cooler climates but don't really seem to fit outdoors or the tropics. What kind of swarm would fit a hot jungle? Leeches! But a swarm adaptation offers only one possibility for leeches, or the filler creature of your choice. How do you get from an idea to a worked-up creature?

One idea is to make your new creature idea not actually a creature in game terms, but a hazard instead. Something like green slime is a good example; it used to be treated as a monster, but what does it really do? It just lies there and turns anything that touches it into green slime. Okay, we could say something similar about leeches. They don't do anything by themselves, but if you go through the leech area (a stagnant pool or tall wet grass or whatever), the leeches drain blood for 1d2 Constitution damage or inflict filth fever or whatever you decide. How do you avoid it? Don't go in the leeched area, like Mikko climbing around the pool. If you go along the edge of the area (say, if Melantha had a water walk spell to cast), maybe you get only partially affected, or not at all. Maybe you have to burn out the little bloodsuckers with fire, or apply a certain amount of salt -- anything is fine, as long as the hazard has some kind of countermeasure (like remove disease with green slime).

If you do want to make your new adversary an actual creature, think about what is most similar to it in the game. Is there already a creature that does what it does? If so, you could still create your new monster just for the sake of variety (say, a predatory tree-dwelling lizard with stats identical to a leopard, or a huge prehistoric hyena that works just like a dire wolf). It saves you time making up new stats and injects some unique local character into your campaign arc.

Other times, there's really nothing quite like what you have in mind. Still, you can find things that are similar to it to use as a model. You're not trying to replicate that monster, but you can compare your creature to the existing one, see where one is stronger or weaker than the other, and calibrate the monster to be what you want it to be. That is helpful in figuring out appropriate CR for new creatures. If your party has actually faced that kind of monster before, you can think about how they approached it and decide how you want to tailor the new monster specifically with your characters in mind. It's possible to overdo that (making monsters designed to go against the characters in your game) but as long as you put thought into the process, why not? The PCs are the characters who are going to face the creature. If you create a monster that they're going to wipe off the map in one round, you're probably wasting your time. The creature won't be around long enough to make any kind of an impression or give you much payoff for your hard work in creating it. That doesn't mean every monster should be a supermonster -- just that you need to consider how you'll use it.

So, back to Eddie's leeches. He likes the idea of the swarm template for the jungle. In fact, all those National Geographic specials about the jungle were all about swarms, so he actually has it in mind to make a couple of new swarm types (see sidebar). He has found lots of interesting individual monsters to drop in here and there, but Eddie loves the idea of the swarm as an emblem of the jungle itself as a character in the campaign -- something that is alive and dangerous. The swarms will really make it feel oppressive and sticky and crawling with unpleasantness, and that's exactly what he wants. A campaign theme is really all about mood, atmosphere, and presentation, and selecting old monsters or creating new ones should be done with an eye toward enhancing that.

All the categories we talked about last month regarding developing a creature template still apply when designing a whole new monster. There are also tips on creating monsters in the Monster Manual and Dungeon Master's Guide, so I'll skip the general advice this time. Instead, I'll encourage you to think hard about what you are designing this new monster to do.

For the leeches, they will be creepy all by themselves, but what will that mean in game terms? The trick of the leeches is that they're sneaky. They have to be hard to spot, so that you can't see them right away and know to avoid them. The Hide skill is necessary. Once you get close, you don't notice they're all over you until they're all over you! Ewwww! So they need some kind of anesthetic power so that you don't notice you're getting attacked right away. But they're a swarm, right? Don't all swarms have distraction as a special power? Maybe this is the one swarm that doesn't. Or maybe you're distracted by it only after you notice. When they're just quietly sucking out your lifeblood, you don't know to be terribly afraid yet! Also, even when you get out of the area where the leeches swarm, they keep hanging on to you, so there should be some kind of mechanism to represent the leeches that remain stuck to their victims. Plus, leeches are carriers of disease. A glance at the Dungeon Master's Guide diseases table (Table 8-2) and how diseases are transmitted suggests that red ache might be a good choice for something that lurks in nasty water and sucks your blood; its also a fresher choice than the overused filth fever.

As a new monster, though, your creature also needs weaknesses. What can one use to stop slugs and leeches? Salt! Your players know that, and they'll figure out a way for their characters to know that, too. Be prepared and figure out the effect of obvious countermeasures ahead of time, so you aren't left there wondering right in the middle of the game, "Hmm, how much damage should salt do to a swarm of leeches?" Don't forget special benefits or vulnerabilities of creature types and subtypes either (in this case, a swarm of vermin).

Leeches, of course, are just one of a zillion possible examples of monster creation, but this illustration hits the basic needs. A leech swarm fills an apparent gap in the monster list. It does something interesting and different. It fits with the theme and the mood that Eddie is trying to create. So he sprung it on his players a little early, before they even get to the jungles. It's always good to keep the PCs on their toes, and when they are trudging through the sodden underbrush of the jungle primeval they'll be wishing it was as easy as climbing around a cave wall to get away from the terrible swarming jungle creepy-crawlies!


Leech Swarm
Diminutive Vermin (Aquatic, Swarm)
Hit Dice: 2d8+2 (11 hp)
Initiative: +0
Speed: 5 ft. (1 square), swim 5 ft.
Armor Class: 14 (+4 size), touch 14, flat-footed 14
Base Attack/Grapple: +1/--
Attack: Swarm (1d6)
Full Attack: Swarm (1d6)
Special Attacks: Anesthetic, blood drain, disease, distraction, lingering leeches
Special Qualities: Darkvision 60 ft., hide in plain sight, immune to weapon damage, salt vulnerability, swarm traits, vermin traits
Saves: Fort +4, Ref +0, Will +0
Abilities: Str 1, Dex 10, Con 12, Int --, Wis 10, Cha 2
Skills: Hide +12*{0 ranks, +12 size}, Move Silently +2*, Swim +10
Feats: --
Environment: Temperate or tropical marshes or freshwater
Organization: Solitary, infestation (2-5 swarms), or epidemic (6-15 swarms)
Challenge Rating: 3
Treasure: None
Alignment: Always neutral
Advancement: None
Level Adjustment: --

A squelching mass of tiny black slug-like horrors engulfs everything it touches, quivering and slithering over every exposed surface.

Leech swarms typically lie quiescent in stagnant pools, waiting for prey to come to them. While they are capable of surviving out of water, they will rarely stray more than 5 feet from the water's edge (though some leeches will cling to creatures after they leave the water).


A leech swarm will move slowly toward any creatures in the water and attach to them, using their anesthetic to remain unnoticed so that they may drain as much blood as they desire before dropping off and returning, engorged with blood, to the water.

Anesthetic (Ex): Unlike other swarms, a leech swarm is not distracting to creatures within it (until they notice the leeches; see below), and in fact often goes unnoticed until it is too late. The victim of a leech swarm's attack must make a DC 15 Survival check to notice the swarm's attack, and a DC 15 Search check will reveal the leeches crawling into and under a person's garments or armor and attached to their skin. This Search check is made with a +1 bonus per point of Constitution drained by the leech swarm, as the leeches become engorged with blood and easier to find.

Blood Drain (Ex): In any round in which it begins its turn with a living creature in its space, a leech swarm will drain blood, dealing 1d3 points of Constitution damage. Once the swarm has inflicted 4 or more points of Constitution damage to that target, the leeches detach and become quiescent again until they have digested their feast (requiring one hour). This has no effect on blood drained from other creatures; a leech swarm may drain blood equal to 6 points of Constitution from each creature within its space. Creatures leaving the swarm after the leeches have dropped off must still contend with lingering leeches.

Creatures with a natural armor bonus of +5 or better are immune to the blood drain attack of a leech swarm and are not subject to lingering leeches, but still suffer normal damage and a risk of disease from contact with a leech swarm.

Disease (Ex): Red ache -- swarm attack, Fortitude DC 12, incubation period 1d3 days, damage 1d6 Str. The save DC is Constitution-based.

Distraction (Ex): Any living creature that begins its turn with a swarm in its square must succeed on a DC 12 Fortitude save or be nauseated for 1 round. The save DC is Constitution-based.

Note that unlike other swarms, a leech swarm's distraction ability comes into play only after the leeches have been noticed. While the anesthetic effect remains in place, creatures are not distracted by a leech swarm.

Hide in Plain Sight (Ex): A submerged leech swarm can hide anytime it is submerged in murky or weedy water, even while being observed.

Lingering Leeches (Ex): If a leech swarm has successfully drained blood from a creature, many of the leeches from the swarm will remain attached even after the creature has left the swarm behind. These leeches will continue to inflict 1 point of damage and drain blood for 1 point of Constitution each round for 1d4 rounds after the creature leaves the swarm. This blood drain does not count against the swarm's maximum drain. The anesthetic ability described above also applies to noticing and finding these lingering leeches. The lingering leeches can be attacked as a leech swarm, and any attack that inflicts even 1 hit point of damage will cause them to drop off (though this does not count against the hit points of the leech swarm from which they came).

Salt Vulnerability (Ex): A leech swarm suffers damage from contact with salt. A pound of salt is as effective against a leech swarm as a flask of alchemist's fire. A handful of salt tossed upon a leech swarm inflicts 1d3 points of damage. The leech swarm or one or more of its victims must be at least partially out of the water to be attacked with salt; salt is ineffective against a leech swarm if it is completely submerged.

Skills: A leech swarm has a +2 bonus on Move Silently checks. A leech swarm has a +4 bonus on Hide and Move Silently checks in water.

A leech swarm uses its Dexterity modifier instead of its Strength modifier for Swim checks.

A leech swarm has a +10 racial bonus on any Swim checks to perform some special action or avoid a hazard. It can always choose to take 10 on a Swim check, even if distracted or endangered. It can use the run action while swimming, provided it swims in a straight line.

Next month: Let's make some magic!

About the Author

Jason Nelson lives in Seattle with his wife (Judy), daughter (Meshia), son (Allen), and dog (Bear). He is a part-time homemaker, part-time medical transcriptionist, part-time Ph.D. candidate in social & cultural foundations of education, and is an active and committed born-again Christian. He began playing D&D in 1981 and currently runs one campaign while playing in two others.

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