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Greybanner Coliseum: Arena Traps and Hazards

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The Arena’s fighting pit has seen innumerable magical and engineered upgrades over its lifetime. The enchanted mechanisms in its walls and beneath the sand allow the Arena Master and his men to quickly, drastically alter the environment between rounds. These alterations begin with walls and inclines before other, more intricate mechanisms are attached. Some have the ability to spit fire, launch poisoned darts, or to trigger when a fighter strays too close. The randomness and unknowable dangers to every fight is one the Arena’s key draws, with audiences often cheering for or betting on the use of these traps to end a fight.

Erwin Redmane oversees the traps with the utmost detail and care. He does so with the assistance of both Eva Cinderbrow and Elias Gilderoy. The former has had a personal hand in advancing both the variety and functions of the traps, though often to the point of Redmane’s resistance. Opposite Cinderbrow is Marla Durand, who vocally opposes the lethality of the mechanisms.

With our recent refurbishing of the Greybanner Coliseum battle map, it’s only fitting to also give you some ways to customize your arena fights. The best way to do this, of course, is with traps! From flamethrowers to whirling blades to thunder grenades, every addition to the arena is designed to add excitement, unpredictability, and tactical options. Perceptive players can identify and use them to their own advantage against unwary opponents. Or maybe a grenade will throw them into a flaming grease puddle that slides them into a spike-filled pit. The possibilities are endless!

All of these traps are designed for the Greybanner Coliseum, found here…

This article is also part of our ongoing ‘Secrets of the Arena’ adventure guide…

Building a Battlefield

Every fight in the Arena features a new formation of obstacles and a new selection of the available traps. Fighters will never know exactly what they are going to face, where traps may be hidden, or who might hold an advantage.

The first step is to modify the Arena’s canvas with a restrained selection of stone walls and rocky inclines. These should be symmetrical so as to not favor one fighter. There should be enough space for movement, particularly if the fight will involve a Large or greater creature, as well as room for traps to be attached to walls and hidden in the sand.

Dungeon Room Builder Demo Map
Looking for some basic stone brick walls and pillars? Our Dungeon Room Builder has multiple tiles for exactly that! Check it out here.

Structures. Stone brick walls or pillars, resembling the ruins of buildings. Each wall is 1 foot thick and 10 feet tall, though they may lower to 5 feet tall at their ends. Pillars have a radius of 1 foot and are 10 feet tall.

Inclines. Steep, rocky slopes that separate levels of the battlefield. Each incline is 5 feet wide and 5 feet high and counts as difficult terrain.

You can then select an interesting set of traps for each fight or roll a d12 up to 5 times and consult the table below to determine the design of each trap. Depending on the trap, they may be free-standing or attached to an existing wall or other obstacle. Below the table is a list of traps and their functions.

d12Trap
11d4 + 2 rotating pillars
21d4 + 1 dart throwers
32d4 spinning blades
42d4 bladed snares
51d4 + 1 force crystals
61d6 + 1 spiked plates
71d4 + 2 circular pillars
81d4 + 1 grease puddles
91d4 + 1 fire blasters
101d3 + 1 thunder grenades
111d3 + 1 lightning arcs
121d4 open pits

You may wish to increase or decrease the number of each trap depending on the makeup of your fighting space. They should be a present threat without forcing fighters to be constantly making saving throws, taking damage, or being too nervous to move. Likewise, they exist specifically as additions to a fight. The impact of the traps should ideally not outweigh that of a fighter or their opponent.

Arena Traps

Bladed Snare

On activation…

A mechanical ‘CLUNK’ sounds as metallic jaws burst from the sand around your foot.

Placement. Hidden below the sand, requiring a DC 15 Wisdom (Perception) check to spot the tips of its teeth.

Trigger. Any creature that steps within the snare’s 5-foot square.

Effect. The trap’s jaws close around the creature’s foot. The creature that triggered the snare must make a DC 13 Dexterity saving throw. On a failure, the creature takes 3 (1d4) piercing damage and is held by the trap. On a successful save, the creature takes half as much damage and isn’t caught. A creature caught in the trap has its speed reduced to 0 and has disadvantage on Dexterity saving throws.
A creature can use an action to free itself or another creature caught in the trap.


Circular Pillar

Circular pillars of stone are planted in the sand, each one with an attached…

On activation…

You hear movement beneath your feet, moments before each of the circular pillars suddenly spin, stopping to face a different direction.

Placement. Rising from the sand, at least 20 feet apart from one another. The pillars are 10 feet tall and have a radius of 1 foot. A single offensive trap is attached to each pillar.

Trigger. Initiative count 20 (losing initiative ties).

Effect. The pillars rotate to a random direction and the traps activate. Roll a d8 to determine the direction (e.g. 1, the trap faces north; 5, the trap faces south).

Roll a d6 and consult the table below to determine the attached trap. Refer to each trap’s entry for their function and description, and note that some operate differently depending on their position.

d6Attached Trap
1Dart thrower
2Force crystal
3Grease puddle
4Fire blaster
5Lightning arc
6Stone walls (1 foot thick, 10 feet tall, and extending 10 feet out)

Dart Thrower

Small holes recede into the wall in a grid, carefully nestled in dark corners between the bricks.

On activation…

A ‘thunk’ is followed immediately by a barrage of smaller ‘clicks’, each one launching a small dart from the wall at blinding speed.

Placement. Hidden in any 5-foot long section of wall, requiring a DC 15 Wisdom (Perception) check to spot.. Multiple dart throwers may be placed next to each other.

Trigger. A 5-foot wide, 15-foot long line of pressure plates (5 feet each) extend forward from the trap, hidden beneath the sand.

Effect. A barrage of poisoned darts is fired straight forward from the wall. The darts have a range of 20 feet and a +6 to hit, dealing 4 (1d4 + 1) piercing damage on a hit and poisoning the target until the start of their next turn. The trap then resets.


Fire Blaster

The carved, twisted face of a dragon extends from the surface. Its eyes are red crystals above an open mouth with nothing but black inside.

On activation…

An orange light builds deep inside the mouth of the stone dragon head, before a plume of fire blasts out.

Fire Spell Assets - Preview
If you want to add that extra little spice to your traps and map, have a look at our Fire Spell Assets. Take a look at the 24 fiery effects here.

Placement. Attached to a wall, pillar, or other structure.

Trigger. The traps ‘eyes’ detect any visible creature that moves within a 15-foot cone directly in front of it for the first time on a turn.

Effect. A gout of fire erupts from the trap’s mouth in a 15-foot cone. Any creature in the cone must make a DC 13 Dexterity saving throw, taking 5 (1d8) fire damage on a failed save, or half as much damage on a successful one. The trap then resets.
The fire also ignites any flammable objects in the area that aren’t being worn or carried, including puddles of grease. Any creature that steps into burning grease for the first time on a turn or that ends its turn there takes 5 (1d8) fire damage.


Force Crystal

A pale blue crystal the size of two fists is set in an iron ring base, glowing dimly.

On activation…

The crystal pulses with a white light that coalesces at its tip, firing off a missile of energy that spirals and seeks its target.

Placement. Embedded in a wall or pillar, or floating 5 feet above the sand, locked in place.

Trigger. Any creature that steps within 15 feet of the crystal for the first time on a turn or that starts its turn within the crystal’s range.

Effect. A glowing dart of force flies out in a line at its target, dealing 4 (1d4 + 1) force damage to the creature that triggered it.


Grease Puddle

A metal pipe extends several inches from the surface, its interior stained black.

On activation…

You hear a low rumble before a flow of slick, black grease pours from the pipe and coats the ground.

Placement. Set in a wall, pillar, or the ground.

On a vertical surface…

Trigger. A tripwire (DC 15 Wisdom (Perception) check to spot) runs 20 feet forwards from the trap.

Effect. Grease bursts from the pipe to cover a 10-foot-wide, 30-foot-long line in front of its opening. The grease is difficult terrain. When the grease appears, each creature standing in its area must succeed on a DC 13 Dexterity saving throw or fall prone. A creature that enters the area or ends its turn there must also succeed on the same saving throw or fall prone. The grease lasts for the duration of the fight.

On the ground…

Trigger. 4 hidden pressure plates (5-foot squares each) surround the pipe, which rises from their shared corner.

Effect. Grease pours upwards and spreads to coat the ground in a 10-foot radius around the pipe. The grease is difficult terrain. When the grease appears, each creature standing in its area must succeed on a DC 13 Dexterity saving throw or fall prone. A creature that enters the area or ends its turn there must also succeed on the same saving throw or fall prone. The grease lasts for the duration of the fight.


Lightning Arc

The sculpted face of a horned, devil-like creature is attached to the wall. Its eyes hold blue gems and its mouth is charred.

On activation…

Static prickles your skin. You turn to see the stone devil’s head glow with white-blue energy before a bolt of lightning strikes out from its mouth.

Placement. Attached to a wall, pillar, or other structure.

Trigger. The traps ‘eyes’ detect any visible creature that moves within a 30-foot line directly in front of it for the first time on a turn.

Effect. A bolt of electricity shoots out in a line from the trap, continuing until it strikes a solid surface. Any creature in that line must make a DC 13 Dexterity saving throw, taking 5 (1d8) lightning damage on failed save, or half as much damage on a successful one. The trap then resets.


Open Pit

A pit descends into the sand, roughly 15 feet deep and hemmed with stone bricks.

Placement. A 10-foot radius and 15-foot deep hole in the ground. An additional trap may be waiting at the bottom of the pit.

Trigger. Falling in the pit.

Effect. A creature that falls in takes appropriate falling damage and activates the additional trap, if there is one. The pit’s walls have enough footholds and variation for a creature to climb out.


Rotating Pillar

Square pillars of gray bricks stand in the sand. Attached to two sides of each are…

On activation…

You hear a click from each of the pillars around you, before a muffled grinding of gears. Each one slowly rotates a quarter of a turn and clicks into place again.

Placement. Rising from the sand, at least 20 feet apart from one another. The pillars are 2 feet wide on either side and 10 feet tall. Offensive traps are attached to two opposite sides (north and south, or east and west) of the pillars.

Trigger. Initiative count 20 (losing initiative ties).

Effect. The pillars rotate 90 degrees and the attached traps are triggered.

Roll a d6 and consult the table below to determine the attached trap. Refer to each trap’s entry for their function and description, and note that some operate differently depending on their position.

d6Attached Trap
1Dart thrower
2Force crystal
3Grease puddle
4Fire blaster
5Lightning arc
6Stone walls (1 foot thick, 10 feet tall, and extending 10 feet out)

Spiked Plate

Sharpened pieces of metal are attached to a base plate, violently protruding at different angles.

On activation…

You hear a heavy, mechanical shift, and the plate of spikes swing at you with explosive force.

Placement. Attached to a wall or the ground.

Trigger. Stationary, or a 5-foot square pressure plate immediately adjacent to the spiked plate.

Effect. Any creature that enters the spikes’ space for any reason immediately takes 5 (1d8) piercing damage. If the plate is activated by a pressure plate, it either swings or extends towards the creature that triggered it. That creature must make a DC 13 Dexterity saving throw, taking 5 (1d8) piercing damage on a failed save, or half as much damage on a successful one. The trap then returns to its place and its trigger resets.


Spinning Blades

Dungeon Trap Tokens, page 2
You might notice that a lot of these traps are based on our Dungeon Trap Tokens, which you can find here.

A metal ring mechanism supports four bladed arms that spin in a whirlwind of steel.

Placement. Centered within a wall, or free-standing on a support that sticks out from the sand.

Trigger. Always active.

Effect. Any creature that steps or is moved into the blades for the first time on a turn or that ends its turn there takes 5 (1d8) slashing damage.


Thunder Grenade

On activation…

A rush of air blasts upwards from the ground, scattering the sand. A clay orb shoots up out of it. It glows with runes for a fraction of a second before releasing a thunderous blast.

Placement. Hidden below a small mound of sand, requiring a DC 15 Wisdom (Perception) check to spot it.

Trigger. A hidden ring of pressure plates surround the trap for 5 feet in every direction.

Effect. A grenade launches 5 feet up into the air and then explodes in a 10-foot-radius sphere. Any creature in the sphere must make a DC 13 Constitution saving throw, taking 4 (1d6) thunder damage and being pushed 10 feet away on a failed save. On a successful save, the creature takes half as much damage and isn’t pushed. The trap then reloads and its triggers reset.

The traps were all designed with several basic thoughts:
Each one should be unique and interesting. Damage types, effect areas, and saving throws are repeated as little as possible, to avoid traps feeling like reskins of each other or becoming predictable.
The traps are balanced for levels 1-5. Each one only deals a single damage die, with moderately difficult save DCs/hit bonuses. Hidden traps come with a DC of 15 to balance them being hidden with rewarding characters that have heavily invested into Wisdom and Perception in character creation.
Direct damage is balanced against additional effects. Traps that only deal damage (blades, spikes, fire, lightning) all deal 1d8 but do not put the victim at any other disadvantage. They are also visible and/or include a save to lower the damage. The thunder grenade is lowered to 1d6, as being moved 10 feet is unlikely to sway a fight. By contrast, both the snare and darts only deal 1d4 as being held in place or poisoned can greatly impact a 1v1 fight on their own.

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