Spell Spotlight: Prismatic Wall
Spell Spotlight is a series that focuses on excellent, problematic, underappreciated, overrated, or just plain weird spells in Dungeons & Dragons. As I pored over all the 9th-level wizard spells in D&D in search of spells to give to my ultimate lich, I came across a spell that I’d never used. I was aware of this spell, and I’d seen its art in prior editions of the game, but I’d never read its text before. I saw the ultimate defensive spell.
I saw prismatic wall, and I instantly started planning a new campaign just so I could use this single spell. Because not only is it cool as all hell, it demands that an entire campaign build up to it. It’s one of the few spells in D&D that poses a fascinating puzzle to the players, and I’m here to break down what makes this spell a fantastic addition to any DM or player’s arsenal.
What Does Prismatic Wall Do?
Take a moment to read over that spell’s text. Essentially, this spell creates a towering wall of seven radiant layers, one for each color of the rainbow. In addition to the entire wall creating waves of blinding light, each layer has a different defensive effect, such as protecting anything behind it from spells, negating ranged attacks, damaging creatures that touch it, and even shifting creatures that pass through it to a different plane. In short, you do not want to blindly run into this wall.
A Player’s Perspective
This spell is incredibly powerful as a player. It lasts for 10 minutes without requiring concentration, allowing you to maintain other powerful offensive spells while creating an ultimate shield. That said, this spell can actually make it difficult for you and your allies to engage the enemy, since its effects work both ways; neither you nor enemies can use ranged weapons while the red layer is active, nor can either of you use ranged spell attacks while the orange layer is active (or spells at all, because of the indigo layer!), and all of these layers prevent combatants from passing through it. The caster can allow its friends to pass through the wall when the spell is cast, but moving through the wall to cast is still dangerous, leaving you open to opportunity attacks and readied attacks.
However, imagine a different scenario.
You stare up at the final boss of the campaign, an ancient red dragon that has destroyed cities and killed thousands of innocents. For two years of game time you have fought against this dragon and its minions. You are flying atop a carpet of flying while the beast taunts you.
“Unleash your strongest spell, puny mortal!” the dragon cackles. “No magic can penetrate my scales… I am legendary! I resist all harm!”
You clutch your staff of power and grit your teeth. Ash fills your lungs with every breath, but you rasp out an incantation and smirk wearily at the dragon.
One by one, bands of prismatic light wrap encircle the monster until it disappears completely from sight. In the place where the dragon once flew is now a blinding globe of radiant light.
In a player’s hands, prismatic wall’s most powerful application is actually offensive, not defensive. (Though, in fairness, its flexibility is a huge part of its power.) Even creatures with the Legendary Resistance feature can’t resist being surrounded by a 30-foot diameter sphere with no saving throw. Now the creature is trapped within the sphere, and it must try to pass through all seven layers before it can resume attacking the party. If your Dungeon Master doesn’t know about the different powers of this magic seven-layer cake of death, the creature encircled in it may just try to pass through the walls of light… and have to make a Constitution saving throw to avoid being blinded, then seven Dexterity saving throws to avoid taking 50d6 damage of various types, then being restrained for up to three turns and possibly petrified (imagine the satisfying crunch when the petrified dragon shatters on the ground one thousand feet below!), and then avoid simply being kicked out into the Astral Plane.
Even if the DM does know about the power of prismatic wall and wisely chooses not to try and push through, you’ve still probably bought yourself 10 minutes to wipe out the boss’s minions without hassle, stop its evil ritual, drink potions, cast healing spirit, or do any number of out-of-combat actions. Let’s see meteor swarm do that!
A Dungeon Master’s Perspective
Of course, you can do the same thing as a Dungeon Master. Trapping the entire party in a globe of destructive magic is essentially a 10-minute-long time stop for you and your minions. I decided ultimately to not give this spell to the lich when I redesigned its spell list for a few reasons. First of all, while I would absolutely run a flamboyant rainbow lich who kills his enemies in an arcane rave, that might not be to most peoples’ tastes. Might be a little anti-thematic to give this spell to a musty, dustbag lich. The other reason is, as I mentioned earlier, you can’t fight back through this wall. Ranged attacks don’t work, spell attacks don’t work, and spells don’t pass through the wall period. The caster can designate creatures that can pass through the wall unharmed, but this can still potentially be dangerous if monsters use the Ready action to attack characters that step out from behind the wall .
But I took some time and thought about that and I remembered: liches and other final boss-worthy creatures have minions, lair actions, and other plot-specific DM powers at their disposal. Visualize this encounter:
The Grand Theurge of the Cult of the Burning Hate, a sect of nihilistic Pelor-worshipers, stood before the altar of his god, flanked by his pontific guard and a horde of blazing, corrupted celestials created by his twisted following. Prismatic light flowed in through the gorgeous stained-glass window behind him, bathing his pure-white robes in kaleidoscopic colors.
The party entered the chamber. They were heroes the likes of which the world had never seen, equipped with powerful relics and mighty spells. The Grand Theurge smiled as they entered his inner sanctum. “Welcome, heretics!” he shouted, spreading his arms wide as if to embrace them. The heroes stood at the other end of the room, a full hundred feet away from the Grand Theurge and his minions. “If you think you can stop my ritual… if you think you can halt this revelation, you are sorely mistaken. Ten short minutes. That is all you have until the time of ascension.”
The Grand Theurge raised both hands to cast a spell, but the party’s wizard reacted swiftly with a counterspell. But one of the pontific guard was prepared with a counterspell of his own, cast at 7th level. The prismatic colors cast by the stained glass window behind the altar sprung to life, creating a wall of incredible color that stretched from the floor to the ceiling between the heroes and the Grand Theurge. The Theurge and several of his minions stood behind the wall, while a host of his fiery minions were partitioned on the other side—and prepared to attack.
From here, the “Grand Theurge” may not be able to cast spells at the party, but there are many factors working in his favor: in 10 minutes when his prismatic wall falls naturally, his ritual will complete, a sort of non-standard “game over” for the party, so they can’t just wait out the spell. He has minions on both sides of the wall; the minions on the party’s side will harass them as they try to penetrate the wall, and the minions on his side will be there to assist him when they eventually breach it. Since the Grand Theurge is a legendary creature in his own lair (I’d probably homebrew his stats, but for the sake of this scenario let’s just call him a lich with a mix of wizard and cleric spells), he gets to dish out incredible pain every round using his lair actions on initiative count 20.
Since the wall is made of opaque light, any effects that require the High Theurge to see a target or a point fail, and unfortunately that’s all three of the lich’s lair actions! However, a well-placed clairvoyance sensor on the other side of the wall before the fight begins will allow the Theurge to see his enemies, even with the wall in the way! Cruel? Yes. Clever? Very.
With all of these stress factors in play, the fight becomes more than a simple beat-down. It becomes a dynamic encounter that includes not just a challenging spellcaster, but also rising tension through a race against time, and even a puzzle!
What puzzle you ask? Well…
Overcoming a Prismatic Wall
A prismatic wall can’t be dispelled, and is unaffected by an antimagic field (and, implicitly, other forms of antimagic, like a beholder’s central eye beam). Instead, each layer of the wall must be destroyed individually, and only through very specific means. If you haven’t already, open the spell description in a new tab and take a look at how you destroy each layer of the wall. Some of these methods, such as the green layer, are incredibly esoteric! One might be able to guess that you have to deal cold damage to the red wall, but the green wall can only be pierced by passwall and similar effects? What!?
It feels like one of those old NES games that you needed to subscribe to Nintendo Power in order to beat. I’m thinking of Castlevania II: Simon’s Quest and its many infamous, esoteric puzzles. So if the players are unprepared to face a prismatic wall, they may find themselves confused, unhappy, and maybe even compelled to cheat by reading the spell description in the Player’s Handbook. None of those outcomes are ideal. Even though prismatic wall is a 9th-level spell, overcoming it should feel like a challenging puzzle, not a frustrating chore.
What this means is that in order to use prismatic wall to its full potential, it should be a part of your overall campaign design, not just your encounter design. I’m a big Nintendo fan, and while I just criticized older games for their obtuse design, there is something modern Nintendo games do exceptionally well: teaching players how to play their games and crack their puzzles. My opinion is that all Dungeon Masters are level designers, and learning to be a better level designer has made me a better Dungeon Master, and vice versa. How would Nintendo teach players to overcome this obstacle?
One way of teaching players to overcome a prismatic wall could be to tell the players outright, explaining each layer’s weakness but that’s just bland exposition, and it’s reliant on metagame knowledge. Another way could be to let the characters find a scroll of prismatic wall that explains the spell’s secrets, and while that’s a step in the right direction, it’s still telling, not showing. As Dungeon Masters, we’re both storytellers and game designers, and that means it’s our job to show, don’t tell. So, how would the level designers at Nintendo do it? I’ll let Mark Brown, a man whose videos have taught me more about game design than any class, explain it in just 5 minutes using Super Mario 3D World as a lens.
The concept of the 4-step level design doesn’t map perfectly to what we’re doing here, but let me quote the important part: “[each level] has a satisfying arc of introduction, development, twist, and conclusion.” By introducing each layer of the wall individually, say, by using only the red layer of a prismatic wall to block access to some optional treasure in a low-level dungeon, the players can learn about how to overcome the wall in a safe, pressure-free environment. Then, by developing the idea, you can place that same wall in a more tension-filled scenario, such as in a fight with a spellcaster, shielding them from ranged projectiles while still allowing them to fire spells through. If you want, you can even twist the idea further; perhaps give enemies a “red prismatic bubble” magic item that moves with them and makes them immune to ranged weapon attacks until it is destroyed by taking 10 cold damage.
You can prime the players with ways to tinker with each layer of the wall in isolation throughout the campaign, then finally allow the idea to reach its conclusion when you deploy the full seven-layered prismatic wall in a climactic encounter. Now the idea is no longer a frustrating “where’s the walkthrough” puzzle, but a satisfying test of everything they’ve learned throughout the campaign.
The Burning Eight: A Campaign Idea
Maybe it’s a bit much to plan an entire campaign around a single spell, but I’ve been struck with a fever for this idea and I can’t rest until it’s all on paper. This is The Burning Eight, a setting-neutral campaign idea built entirely around prismatic wall and ways to teach players to overcome it. If I were to run this campaign, I would set it in Tal’Dorei, the setting of the first campaign of Critical Role, because the power of gods, heresies, and divine meddling are so important to that setting, and because it uses a modified version of the Dawn War pantheon from the Dungeon Master’s Guide, which is vital to this campaign.
Words and phrases in parentheses translate terms from this setting-neutral concept into similar terms for use in Tal’Dorei.
The sun god Pelor (the Dawnfather), is transforming from a benevolent deity of Neutral Good to a wrathful deity of Neutral Evil. In his battle against Tharizdun (the Chained Oblivion) in the Dawn War (the Divergence), a seed of Tharizdun’s evil was planted in his heart. Now, nihilistic cultists seek to hasten Pelor’s transformation into what they believe to be his true form—a sun that does not give life, but one that destroys it. They seek to transform him into the Burning Hate, a fiery star that they can use as a weapon to destroy their enemies.
The Cult of the Burning Hate is led by a man who calls himself the Grand Theurge, a smug, self-righteous priest cast out of Pelor’s church for heresy. He seeks to destroy the church of Pelor as retribution for his excommunication, for transforming Pelor into a deity of evil will not only augment his power as a worshiper of the Burning Hate, but sever the divine connection from all of Pelor’s current followers as their god is destroyed and reborn.
The leadership of the Cult of the Burning Hate is comprised of eight spellcasters; seven that represent one color of the visible spectrum, and the Grand Theurge who represents all visible light. In combatting the Roland the Crimson, for example, the characters will fight combat not only this wizard’s fire magic but also learn about the red prismatic wall in isolation, as described earlier in this article. These eight spellcasters have entrenched themselves in the nations of the realm in an attempt to recover powerful magical artifacts (the Vestiges of Divergence) in order to allow the Grand Theurge to conduct his ritual of transformation.
In this campaign, the red wizard Roland the Crimson has infiltrated a society of fire elementalists (the Fire Ashari). The orange cleric Oumak the Ochre has become the religious advisor to the Church of Pelor (the Dawnfather) in the capital city (Emon). The yellow bard Yvonne the Golden is a traveling performer that frequents high-class bars around the land, but has a lair in a gambling city (Kymal). The green druid Gessylir the Verdant has become the advisor to the monarch of the elves in their home city (Syngorn). The blue druid Bolivar the Cerulean has supplanted the ruler of a clan of water elementalists (the Water Ashari). The indigo paladin Ivar the Ultramarine has become the new ruler of a major trading down (becoming the Margrave of Westruun). The violet warlock Viola the Amethyst has assassinated and replaced the head of a major dwarven clan in their home city (Kraghammer).
Finally, the white cleric, the Grand Theurge, Wilhelm of Many Colors, has become the ruler of Pelor’s holy city (Whitestone). In Tal’Dorei, he may be one of Lady Vex’ahlia and Lord Percival’s sons, or perhaps this campaign takes place in a completely different time period, before the adventures of Vox Machina.
This campaign toys with the common dichotomy of light and darkness by casting a Light cleric as the ultimate enemy of the campaign. Giving the good-aligned PCs free reign to use dark magic to combat evil light is a fun twist for PCs and DMs alike. Each of these antagonists wields different spells and a different color of the prismatic wall, eventually leading to a climax with corrupted celestials of flame and hatred… and the full prismatic wall itself.
James Haeck is the lead writer for D&D Beyond, the co-author of the Critical Role Tal'Dorei Campaign Setting, and a freelance writer for Wizards of the Coast, the D&D Adventurers League, and Kobold Press. He's honestly surprised that this one spell came up with an entire campaign idea, but he can't wait to find a group to run it with. He lives in Seattle, Washington with his two prismatic spheres, Mei and Marzipan. You can usually find him wasting time on Twitter at @jamesjhaeck.