Drawing Battle Maps – 9 Tips For Awesome Action Scenes — RPT#636
Tactical Mapping – Mondo Map Tips For Awesome Action Scenes
From: Johnn Four
Roleplaying Tips Patrons voted this as one of the top topics to delve into for December. A peeve I have with many published adventures is bland action scene maps. I was just looking at a module last night, in fact, and was studying the maps. Little inspiration to be had in them, unfortunately.
You can make combats and action scenes better just by creating interesting maps. That’s because every encounter operates within a certain structure. And the structure influences how encounters will run – before gameplay even starts!
For example, if the map presents confined spaces, the party’s options and tactics will be much different than if encounters take place in large, open places.
The map acts upon encounters in subtle, silent, and significant ways. If you change the structure, you change the outcome. Therefore, change the map and you change gameplay. That’s pretty powerful once you realize this force at play. There are many such lurking structures that affect our games, and we probably don’t recognize them all and how they affect the fun.
Well, maps is one of those forces, and today I’d like to share some tips so you can see behind the curtain and understand the levers at your disposal to make action scenes better.
Make Areas Bigger For More Gameplay Options
Movement is a core feature of any game. Even if you run action scenes in the theater of the mind, without the grid, characters and foes will still want to move around.
Scarps, tunnels, and rooms give lots of interesting and discreet encounter locations to this map while still allowing lots of area for movement.
The first thing to consider is how big an area your map and action scene covers. The hidden structure here is:
Large areas add more options.
This isn’t good or bad. It’s just something to be aware of so you can design with purpose and for whatever effect you’re trying to GM.
- Give the party more tactical options – flanking, ranged attacks, ranged magic, deceptions
- Give foes the same tactical options – this gives you more to think about and weigh as well
- Lengthen hex time (I describe this below)
- Penalize slow movement
- Can trap fast movers into vulnerable situations (e.g., PCs charge, one gets there two rounds ahead of everyone else, and now faces the enemy alone for two rounds)
- Reward leadership, planning, coordination
- Take longer to game out
- Take extra effort for communication
Large areas have other effects, but these are the major ones. And do you see how they affect multiple aspects of the game? It’s not a case of your design adding +2 to rolls here. Your design will affect the length of time the encounter will take to play out; the amount of stuff you have to figure out, think about, and track; the number of choices PCs have to make, which affects game speed; the amount and type of character abilities made possible or useful in this encounter; the type of foes you select who can take advantage of the extra space (or hide better within it); and more.
It’s pretty neat once you can understand all this just by looking at the map. It makes you feel like you can see a bit of The Matrix behind your games.
Compare an immense cavern to a 20′ x 20′ room with one door. There’s 8 foes in each encounter. Can you picture how each would play out differently, just because of the structure imposed by the map design? In the room, there will be a bottleneck. Instantly, most PCs will be rendered ineffective and inactive. Foe options are also limited. The encounter in these tight quarters will play a predictable script.
But the cavern encounter is akin to freeform play. Will the PCs tighten ranks and proceed with caution, will they scatter and surround their foes, or will they charge like it’s a downhill cheese chase? What spells will the casters choose? Will foes remain stationery? The map offers you more space to add defenses and hazards – do you drop those in?
It’s all very interesting from a design perspective. And each design choice will affect gameplay.
So, the first thing I look at on a map is its area. That’s going to affect a lot of the gameplay. And when mapping, try to create large areas once in awhile to offer this type of gameplay.
What is hex time? It’s tricky to describe, as I’ve never written about it before, but here’s my attempt.
Hex time is the amount of complexity a hex or square of a map introduces to gameplay. And complexity almost always means longer time to game. That also is neither good or bad. But just be aware as you design that fun, pacing, drama, and story hinge on hex time.
For example, if a hex affects PC modifiers, then the game slows a bit each time those modifiers come into play. An empty hex introduces no game lag on its own, so it has almost no hex time. A complex hex that introduces rules, requires a lot of attention to detail, needs to comply with game consistency, and so on, has a high hex time and requires more gameplay time.
An empty hex in an empty room requires almost no game time. You don’t give it any time for detail or description. Unless the PCs search it, the party will move through it or ignore it. The hex has no game effect. It has low hex time.
But if that hex had a secret door, and the door was trapped, hex time goes up. If the PCs search it, you need to figure out if searching succeeds, to describe the door when found, to handle the rules for the trap. Smart PCs will search for traps. Then they’ll try to disable the trap. Then they might search again just to be safe. Then they’ll try to open the door.
All this could be a ton of fun. But just be aware of how your design affects hex time. Because you don’t want to create much hex time on inconsequential stuff or use gameplay on activities your group doesn’t find fun.
Complexity affects pacing, which affects story and drama.
As far as movement goes, area will first determine whether much movement is possible. Lots of possible movement means a more complex encounter.
It also adds a little bit to hex time. Because taken in aggregate, all those empty hexes will get counted for moves, range increments, spell ranges, visibility, and so on. The larger the area, the more calculations are needed each round on basic things like movement and ranged effects.
Interesting movement options here with rising ground, water, and large spaces.
Even in gridless action scenes, you all still need to imagine distances, where everybody is, who’s close to one another, proximity to hazards, and so on.
Also, a bigger area means more possibility of pure movement turns. This not only penalizes slower PCs and foes, but it also means pure move turns go fast, and that might reduce spotlight time. If all a PC does is move on their turn, their turn is over fast, and they didn’t do much.
This can be good if your design is intended to have a “get into position” stage. PCs can choose their approach, buff up, decide on their role and tactics, and then move to get into the most advantageous spot for all that.
But I can think of many big space encounters where the fighters were running their hearts out trying to close with the enemy, while archers and spellcasters attacked from a distance. The fighter turns ended fast. The other players’ turns took the usual time with dice rolls and effects, and were more interesting than, “I move again. Done.
Fighter players tend to get bored fast. 🙂 So look for ways to get them into the action sooner, or create a tactical map where getting into position will just take one or two rounds.
A nice setup in big areas is to spread enemies out. While slow or stealthy PCs tackle close foes, ranged and fast PCs navigate long distance threats.
There’s more to say on movement and tactic map design, which I’ll cover in other tips next.
Imagine a sci-fi RPG and the PCs are in space. They have to think 3D. Foes could approach from any vector.
So too should it be in non-sci-fi games. In fantasy, especially, we get trapped in 2D thinking.
Vertical movement can take the form of flying, levitating, climbing, falling. I guess if you put an orc in a catapult, vertical movement could also be throwing.
Each move type has nuances. Flying means movement in all directions. So think about that. The other move types are mostly limited to straight up and down. You can predict paths better.
With vertical movement, make the answer to these questions as interesting as possible for your map:
- What do they see? e.g., Climb a tree to scout what’s ahead and give the party shocking news.
- What makes moving vertically a challenge this time? e.g., strong winds, nausea fog, carnivorous dire seagulls.
- Can fliers and climbers be detected?
- How will foes react when PCs go vertical?
- Are there multiple levels to perch on or operate from? e.g. Treehouses, battlements, or solid clouds.
The goal is not to necessarily make things more challenging. Instead, the goal always is to make things more interesting.
In your map designs, don’t add strong counter winds just to make life difficult for the PC who has the Ring of Flying. That gets frustrating with repetiton. Instead, design so the flying PC has new situations, tricky choices, and fun gameplay. Sometimes that’ll be challenging wind shear. Other times it might be treasure dangling from a tall tree killer bees have used for home. And in other encounters it’ll be a cool, hidden, tactical spot for the PC to fire off good shots from till the foes get out their crossbows.
Draw To Funnel PCs Into Danger
Make tactical maps more interesting by using the layout to hook players deeper into danger.
The number one way to do this is through curiosity. “What’s behind the door that smells like sweet perfume?
Curved passages, secret doors, and cool design make this otherwise linear map an intriguing funnel.
Here are a few mapping techniques to create curiosity:
Block Line Of Site
Corners, obstacles, portals. Make it so fog of war doesn’t reveal much until it’s too late.
Twisty corridors, strategically placed doors, stairs. These things prevent the party from getting all the information they want to make perfect choices.
A hole in the wall invites more curiosity than a standard door.
Instead of putting walls up and doors everywhere, just partially block the PCs’ senses.
For example, a wall that forces a turn in the corridor is like bacon for characters. They’ll want to sneak up and peek around the corner every time. If it was just a door, then the party would relax. I don’t know why. I guess they feel they have more control because they can keep the door shut, spike it closed, choose when to open it.
But an open corridor must be investigated. It itches if they don’t check it out. If you draw a straight line corridor where they can see how it ends, then you create no mystery. But if the corridor turns and goes beyond line of sight, dips, or climbs, then it’s an open loop and the PCs will feel obliged to investigate.
Figure out the range of vision and extend the map beyond that. This forces the PCs to move forward to see what’s out there.
Don’t forget up. A 100′ ceiling shrouded in darkness makes PCs nervous. Drip some blood on the fighter, and he’ll go crazy. “What’s up there?! I can’t see anything! I’m being bled on!” If the PCs can’t illuminate the ceiling, they’ll hustle on through, funneled to the next place you’ve designed.
Employ Other Senses To Entice
Of the three major senses, vision is shortest. Sounds and smells travel further. And sound travels fastest.
Use the two other big senses to funnel PCs as desired. Use senses and details as hooks to draw the party further into your map.
And combine this with limited vision designs to keep the party curious and nervous.
For example, the corridor turns up a ahead. But the PCs can hear distant growling coming from somewhere beyond the turn.
Have sounds and smells move if the PCs fail to do so to draw the party forward.
Create Good Ambush Zones
Give foes advantage through ambushes. Give PCs interesting options to create their own.
Narrow, linear maps fail to inspire. Instead, open places on your map up for movement. Then provide terrain features and objects that make great hiding places.
Cast shadows, block vision, think upwards to present ideal map zones for ambush.
If the PCs are exploring, then have foes use these places to gain surprise. If the PCs retreat, have foes ready, because players rarely play cautious in explored areas.
Scarps here allow many ambush areas, as does the river side passage.
With dynamic foes or if PCs know about foes in advance, they can use ambush zones for their own tactical advantage. They can try to trick enemies into the ambush, or if they get ahead of enemies, the PCs can lie in wait, the tables turned for a change.
Another map tactic is offering multiple approaches into ambush, camp, or encounter zones. This makes setup more difficult and spreads enemies or PCs out as they try to cover multiple locations.
However, this design also allows interesting tactics. For example, flanking. Or, mis-direction as the bait gets far enough ahead to take the secret passage back to the ambush spot.
Also, callout ambush spots to tactical and fighter PC types who’d recognize them. This creates instant tension, especially if you give false signs of an ambush, such as an animal just out of sight disturbing the terrain. And in cases of actual ambush, giving players a heads-up puts gameplay back on them to react, plan, and take risks.
Last, don’t forget about foe lookouts. Smart enemies will want advance warning of murder hobos approaching. So design maps to give enemies good places to spot PCs before the PCs spot them.
Plot Or Foil Escape
This one is important if you want recurring NPCs. Draw at least one great escape route on your map. Smart NPCs will install escape routes in their lairs. Even the good guys need a tunnel to escape a siege.
Villains should have multiple escape plans because they won’t know if foes will come at them with force, subterfuge, magic, or the blessings of a meddling god.
Deep pools, wells, dark crevasses, stairs, and magic portals all offer potential escape routes. Where would you place the villain’s lair on this map?
Vampires in old D&D modules offer classic escape plans. They turn into gaseous form and ooze through holes or cracks to safety.
Secret doors and passages work well. Note that to escape you don’t have to make a secret door impossible to find, you just need to buy enough time to get away and foil pursuit.
Here are example ideas for escape routes to map:
- Secret passage outside
- Passage that loops back to the entrance
- Fly away on a pterodactyl
- A maze with many routes
- Fire pole
- A slide
Map To PC Powers
Make a list of all the interesting abilities and powers the PCs have. Especially ones concerning:
- Changing matter (i.e., rock to mud spell, go ethereal)
- Extra senses
- Vulnerabilities to certain materials (i.e., kryptonite, can’t swim/heavily armoured)
With list in hand, make maps that involve this checklist. Feature something from every PC, if you can.
Your goal is to create uncertainty. When outcomes are uncertain, a good game is afoot.
So if one PC can climb well, design a map where climbing will come in handy at least once, then make the outcome uncertain. That could take the form of a difficult skill check, or if you want to Say Yes, make the destination uncertain – what’s on the ledge?
Another example, swimming. PCs who swim well, can hold their breath for a long time, or can breathe underwater, often don’t get to use their ability. In that case, add deep water to your maps from time to time. Water-filled wells, water caves, deep rivers, deep pools, fountains with a hole in the bottom.
There’s no easy solution for every power. You’ll need to get creative sometimes. A PC with x-ray vision, for example. How do you make that an interesting map feature? I think that is part of the fun of GMing though, being met with design challenges and using your imagination. If you get stuck, hop online and ask other GMs for ideas.
The key here is to map character features to, well, maps. 🙂
Use Hazards To Increase Damage
In Faster Combat, I teach GMs how to make combats faster and more exciting by focusing on damage.
Increasing defenses just creates grinding. Swing, miss. Swing, miss. Swing, miss.
But increase damage, and suddenly perceived threat level goes up. Players get excited and maybe fearful. Everyone pays attention and starts trying to survive instead of grind.
That’s why you should try to hit the party with a foe’s most damaging attack at the start of combat. Kick things off with a surprise bang. When you lay down a ton of damage, even if that’s the only time a foe can use that, it increases the uncertainty. Either the players don’t know their enemy only has a one-shot massive attack and are fearful the rest of the encounter (especially if you bluff with “recharge” hints and such), or the players feel vulnerable from the start and are nervous the rest of the encounter.
Map in dangerous hazards that do extra damage. These will put pressure on characters to finish encounters faster, and they increase overall drama. If players respond to such pressure, then it’ll make them more creative, as they try to figure out how to bypass the hazard with minimal suffering.
You can also use hazards for funneling. The clear path offers least danger, so characters will likely take that route and you can plot accordingly, all just because of your map design.
But avoid hazards that increase defenses all the time. Do provide cover or ways to enhance PC defensive abilities once in awhile, so players might take bigger risks or have fun feeling powerful and invulnerable. Otherwise, focus on hazards that do damage, like a gas-filled area set to explode on first contact with spark or flame, or round boulders unleashed that rock back and forth in their grooves.
Narrow points make interesting map features. They foil rapid movement, expose single PCs to threats, and direct movement perhaps to greater danger.
Use choke points on your maps to achieve those effects, as desired.
Doors are typical choke points. Sharp turns in passages. Stairs. Canyons. Paths through debris. Magic gates. Small rooms.
Numerous choke points in this map. How would gameplay change if each square was 15 feet instead of 5?
Learn to spot these areas on your maps. First decide if you want to keep them for effect or if you should widen the area. Then, if you’re keeping the narrow spot, decide how you want to take advantage of it.
For example, use choke points to make encounters harder because the party can only attack with one or two PCs. Or use them to hit the party from front and rear while the party is less mobile.
One great use for choke points is escape tunnels, especially if you don’t need many NPCs to escape. A villain can make a tight squeeze, turn on the flood gates, and activate the golems behind him, for example.
Avoid over-using choke points. They penalize back-rank PCs, such as spellcasters and archers.
However, choke points can also aid player skill. How’s that? Well, player skill is gameplay where dice don’t solve the problem. Players must use creativity, critical thinking, and their imaginations to overcome a challenge. When PCs cannot get in their standard grinding attacks, they will need to get creative to remain relevant to play. This is a bit carrot and stick, but with your enthusiasm and encouragement, you can use choke points to draw players into new types of thinking and playing.
We’ve already chatted about using hazards to funnel the PCs. However, creative game masters can also use hazards to shape combat zones.
Here’s an axiom I just made up. It’s called Anti-Centrifugal Grinding.
The Law of Anti-Centrifugal Grinding says, in any open area, PCs and enemies will run towards the centre to fight it out.
That’s pretty boring!
Try this exercise:
Draw a big circle on a piece of paper. Then a square beside it. And then a triangle beside that.
Look at all those shapes. The Law of Anti-Centrifugal Grinding means the fights will take place in the middle of those room shapes.
So let’s play with this using hazards and features to shape our combat zones.
First, let’s look at entrances and exits. Take two dice and pretend they are doors. Move those dice along the borders of each shape. Move them all around in different arrangements.
Can you see how just moving the entrances and exits can affect the shape of an encounter?
For example, what if enemies and PCs enter the room at the same time? Now think about door location. How does an action scene change when doors are across from each other versus beside each other? Very different gameplay erupts.
Another example, what if the enemy gets two waves of reinforcements? They’ll come through one or both of the doors on rounds 2 and 5. Now how does door placement affect the shape of the fight?
Ok, another exercise. Let’s say in each room shape you’ve drawn, foes are on one side and PCs on the other. The Law of Anti-Centrifugal Grinding says they’ll clash in the middle. But, what if you placed a hazard in the middle? A lava pool, perhaps. No one can meet in the middle anymore! This changes the complexion of your action scene with just one small adjustment.
What if you change the shape of the lava pool? Play with that. For example, if the pool has 5′, 10′, or 15′ wide tendrils and channels. These make it harder to clash toe-to-toe. They’d make spells and ranged attacks more effective. What if you added a zip line across all the lava and the handle was on the PCs’ side? Only one PC can cross at a time. How does that change things?
Now move the lava pool around. Put it near a corner. Make two smaller pools. Move them around.
With any hazards you choose, play with the spaces you are mapping out. Foil The Law of Anti-Centrifugal Grinding and make encounters more interesting just by tweaking your map designs.
Feng Shui your action!
Today we went over a few ways to make your battle maps more interesting. When you change the structure of something, you change its effects. And just by making a few small changes to your map designs, you can have large effects on how your action scenes will play out.
To sum up the three main tips here:
Think of map elements as hooks to create player interest and funnel them
- Use design to foil predictable character actions and encourage creativity
- Understand how design influences your games before play even begins, whether it’s map design, adventure design,
- NPC design, and so on.
- Do you have any map design tips?
Just hit reply,
I’d love to hear them.
Brief Word From Johnn
I see a lot of comments online about how GMs want to minimize prep or they dislike prep. But this week I read a post about how preparing and designing campaigns is its own type of game and a lot of fun. Just building for the sake of building.
I think they’re right. I remember spending more time as a kid working on games than playing in them. I’m not sure when that stopped.
An easy answer is, “when life got busy.” But I also wonder if we’ve let some bad thoughts and habits seep in that also sabotage our fun when we prepare for games.
For example, we adults are prone to perfectionism. Just because we have creation and publishing tools we never had as kids doesn’t mean we need to crank out pro-level stuff.
When it comes to conquering perfectionism, I like Scott McCleod’s point about comics in his great book, Understanding Comics: “Less is more.” Comics with a simpler, less detailed style leave more to the imagination. This draws the reader in. Comics with minute details, CGI shadows, and picture perfect panels do all the work for you and turn you into a passive observer.
Applying this to GMing, I don’t mean doing less prep is better. I mean prep fewer details and bigger ideas.
Instead of detailing the equipment of every NPC, let a random table do that for you during the game and instead imagine between games how the story might unfold. How will NPCs react to the party’s recent chaos? What’s the villain’s next move? How can you turn that boring location into some place wondrous?
I find I do best starting with a map. Whether it’s a map of the world, a dungeon, or a village, it gives me platform for session prep. But you don’t have to open up Photoshop just to make a map. I think that’s where perfectionism and fear of failure comes in. Just draw shapes on a piece of paper. Let gameplay fill in the nitty gritty details, like what furniture is in the room.
If you take this approach and liberate yourself from having to make good stuff, then figure out what you enjoy most about gaming and GMing. Then do more of that. Treat game prep as its own game where the rules are you spend prep time on what you find the most fun to spend prep time on. Create for its own sake.
Grab The Archives In Plain Text Free
Whew, it took a lot of work, but I finally caught the plain text version of the archives up to recent issues.
And just in time for Christmas!
I don’t have a tree to put this under for you, so a link will have to do. 🙂
Please download issues #1-#632 for your offline reading pleasure »
Have a great week!
Reader Tip Request: Crafting Mysteries
A reader requested tips on how to create and run mystery adventures. They are tough to do in tabletop RPGs without railroading or missing critical details.
Do you have any advice or tips you could share on mystery adventures?
If so, please drop me a note. I’d like to do a feature in the future on GMing mysteries.
Monstrous Questionnaire To Make Mythical Monsters
As a companion piece to my GM Tips – Making monsters monstrous video, please find below a quick checklist for creating monsters based on a mythological model. Answering these questions will give a bit of extra background and interest to truly monstrous monsters.
How Was The Monster Created?
- A result of divine procreation with a mortal (answer question 2).
- As a result of a curse (answer question 2 & 3).
- Created by a great power for a specific purpose (answer question 2 & 4).
- Monster is actually a form of lesser divinity or similar power (answer question 6).
If A Divinity Or Higher Power Was Involved In The Creation What Was The Nature Of The Power Involved?
(These descriptions are based on the Greek gods listed on http://www.rickriordan.com/my-books/percy-jackson/explore-mythology/greek-gods.aspx Meet The Greek Gods, but you can substitute your own.)
- Home & family
- Agriculture & farming
- Music, poetry & prophecy
- Moon & hunting
- Fire & the Forge
- Love & beauty
- Merchants, Trade & Thieves
- Wine & celebration
- Underworld & Death
- Messages & Communication
- Magic & spirits
- Luck & Fortune
If the monster is the offspring of a god, then its powers will be related to their parent, although they will normally be reflected on the physical appearance of the creature.
Example: The god of sky may sire a creature with huge wings or that is feathered like a bird.
Example: The god of sleep may give birth to a creature that only exists during the hour of dreams (night-time) or that can only be seen in the time just after waking when dreams are closest to the real world.
Why Was The Mortal Cursed?
- Directly insulting the god.
- Taking actions that directly oppose the god.
- Wronging loyal servants of the god.
- Mis-using a talent/abilities granted by the god.
A mortal cursed by the god will tend to have powers and abilities that reflect those of the deity that cursed them, however they are often made twisted and grotesque.
Example: The god of sky may curse a person to become a monster harpy, a twisted bat-like creature with a barely human face.
Example: The god of sleep may trap a cursed person away from the waking world, allowing them only to communicate in dreams. Or perhaps they cause bad dreams and troubled sleep wherever they go (making people irritable and causing them to turn on the cursed individual).
What Purpose Was The Monster Created For?
- To punish those who oppose the gods.
- To guard something precious (also answer question 5).
Monsters created to punish someone are normally specifically tailored to deny those being punished some aspect of their life they value or require, without simply killing them.
Creatures created to guard something precious are normally encountered only in the vicinity of the thing they are guarding and have senses that cover the area, making it difficult to sneak up and purloin their treasure. However, most such creatures have a method via which safe access to their charge can be obtained in case the gods should seek to send a favoured servant to acquire the item.
Example: The god of sky creates a giant eagle to guard one of his thunderbolts. The bolt lies in a huge nest constructed by the beast on an impossibly tall mountain.
Example: The god of sleep creates a monster to punish a debauched town of celebrants. The creature pursues them through dreams that begin pleasant and turn to nightmares, causing them to wake without the benefit of rest.
Where Is The Precious Item Located?
- In a faraway land.
- In a geographical inaccessible place (the bottom of an ocean, the top of a mountain).
- Protected in a hidden demi-plane accessible only via a portal or when specific conditions are met.
- The item is located inside or is part of the creature itself.
Which Deity Is The Creature Related To Or Affiliated With?
- Pick one of the deities from question 2 (or add your own).
- Then choose a more specialized or specific element that might fall under their portfolio (clouds for sky, nightmares for sleep, vanity for beauty).
- A lesser divinity will have powers and abilities related to its specific portfolio. These will be reflected in its physical form to a lesser degree.
Example: Related to the war god, a lesser-divinity of violence and fury might appear as a huge man with bulging muscles, glowing red eyes, and a permanent expression of fury.By making choices from this list and thinking about the various elements, you should be able to create a monster in the style of the ancient Greek and Roman myths.
Kalkedos the Swamp Troll
As an example: I’m going to create Kalkedos (the swamp troll from the video) by using the questionnaire.
How Was The Monster Created?
As a result of a curse (answer question 2 & 3). Kalkedos killed his neighbour when the man rebuffed Kalkedos’ intent to woo his daughter, drowning the man in the swamps near his home.
If A Divinity Or Higher Power Was Involved In The Creation What Was The Nature Of The Power Involved?
Merchants, Trade & Thieves. As he died, the merchant who was a loyal follower of his god, cursed Kalkedos. The god of merchants answered, lending power to the curse. Kalkedos was transformed into a lumbering, clumsy creature with warty skin green the colour of envy. His mind twisted, he gathers the filth of the swamp to him as his riches, blind to the fact that it is refuse. He lashes out at any who dare try to steal from his treasure.
Bound to the scene of his crime, Kalkedos is unable to leave the swamp unless he receives the forgiveness of the merchant’s daughter (who fled when her father died). Should this happen, and she is able to convince him to leave the swamp, then the curse would be lifted.
Why Was The Mortal Cursed?
Wronging loyal servants of the god. Killing the merchant.