Casting Circles

Casting circles represent a form of ritual magic that has heavy demands on multiple participants, allowing a GM to add new options to a campaign that come with built-in adventures and participation for all the PCs.

Using Casting Circles

The purpose of casting circle rules for GM is to be able to get an entire adventure party involved in major magic events. You can use this to solve unexpected problems that crop up (such as the death of a party member when the party can’t afford to have them brought back, or the loss of a limb or similar major hindrance that takes powerful, currently unavailable magic to fix), as a plot point in its own right (“There is no way to assault the Dread Queen’s inner sanctum… except a casting circle used for a greater teleport!” “But we’re 9th level!” “There is a way…”) or just to give players options on new ways to do things that comes with built-in encounters and adventures.

In short, casting circle rules lets players do things they otherwise couldn’t, but only as permitted by the GM, and only by having at least one side-adventure in doing so. The structure of these rules is deigned to be restrictive enough players feel they have specific benchmarks they must meet, and lose enough for a GM to be able to make them fit any campaign theme or special situation. These are a narrative tool for a GM to use to offer adventure options to solve problems, not a way to give players a raw power boost or allow them to skip encounters the GM wishes to be part of an adventure.

The Basics

Casting circles are complex rituals that call upon the untapped, primal energies of the universe. Not just spells, these are loopholes in the fabric of reality, where if the right acts and materials are brought to the right place at the right time, people of will and importance can draw forth raw eldritch power and shape it to create one specific effect.

A casting circle requires a magical formation of multiple people who perform a ritual to produce a spell effect. The number of people required should meet your narrative needs – if a group of 5 PCs need to accomplish something and don’t seem to be able to find any other way to do it, you can offer them a chance to find a casting circle ritual that happens to nee 5 people.

The effect created by a specific casting circle ritual is normally a specific spell, generally of a spell level the participants can’t otherwise access (though it could just be a rare spell none of them can cast, or a spell-like effect the GM decides is the same power level as a spell of an accessible level even if there is no specific spell that creates that exact effect).

The act of using a casting circle to create an effect is known as “circle work.” Successful circle work requires 5 basic steps.

A casting circle ritual must be found and attuned to a specific situation. A place must be prepared for circle work. The circle work itself must be undertaken, which includes an invocation, one or more tests, the cost, and finally the effect.

Finding Casting Circle Rituals

In general, finding a casting circle ritual to cast a spell effect is as difficult as finding a new spell 3 spell levels lower. Thus, finding a casting circle ritual that creates a 5th-level spell effect is as difficult as finding or researching a new 2nd level spell.

The GM can skip over this step if desired and its appropriate to the campaign. A game set in an adventure academy, or where the PCs have access to libraries of magic options, or have a powerful patron or allied organization assisting them, the ritual may just be something that can be loaned out or bought for a nominal fee.

Alternatively, any effort at research or gathering information to find a specific casting circle ritual can reveal that a copy of the needed ritual can be acquired at a location that is clearly a minor adventure site. For example, an abandoned school of magic might have some rituals carved on the walls of its archives, or there might be a remote location in a wilds area (from basements in the bad part of town to a days travel into actual wilderness or down a cave system known to be recently overrun by threats) where a similar ritual was attempted and the needed information can be gathered.

A casting circle ritual is much more tightly defined than a spell, so normally each ritual can accomplish only One specific thing. Characters aren’t looking for a spell to raise anyone from the dead – they need a casting circle ritual that can bring back a half-elf spellcaster who died as a result of a dragon’s breath weapon. This fact helps casting circles have a limited impact on the world they are introduced to. It explains why casting circles aren’t used for day-to-day tasks, and aren’t the solution to every problem. It also means even if the same kind of issue comes up (such as another party member dying), the players are likely to need to research a new ritual to match the new circumstances. This ensures that a GM doesn’t find allowing one casting circle ritual into a campaign means it is used over and over. And, of course, the GM is always free to say a specific casting circle ritual does not and cannot exist – just because you can use it to raise one creature under one set of circumstances doesn’t mean it can be used to restore life to every NPC the players decide they want to bring back and talk to.

As a general rule, acquiring a casting circle ritual should take the same effort as two typical encounters of a level equal to (casting circle spell effect’s spell level -3) x2. This is also the casting circle’s Base Encounter Level (BEL). Thus if a group of 3rd level characters want to find a casting circle able to duplicate a 5th level spell effect, they should face the same difficulty as two typical 4th-level encounters ([5th level spell -3 = 2] x2 = 4th level encounter).

These can be exploration encounters, roleplaying and negotiation, combat, or some combination of all of those. Or even just spending money equal to the treasure gained from a typical 4th-level encounter, if the PCs have the resources and the GM wants to move along to preparing a casting space.

Preparing a Place for the Circle

“If by my life or death, I can protect you, I will.” The energy to power a casting circle requires the circle workers to have a strong connection to the place they use to do their circle work. This normally requires it to be a place they prepare specifically for the circle, and that generally means overcoming an encounter there. This can be a combat, but it can also be a series of DC 15 skill checks equal to two per circle workers to be involved in the circle.

Ideally the GM should make these different kinds of skills so that each PC is better at one skill check than anyone else. If there’s a PC who isn’t the best at any skill, you can make 2 or 3 or the skill checks have to occur simultaneously, so that the 2nd and 3rd best character at that skill need to attempt it simultaneously.

The skill checks may include inscribing a circle in ancient languages, moving heavy objects into precise alignments, making a series of stones or other markers with crafting skills, aligning objects within the area to represent the natural flow of energy in the location, or to respect and invoke its history, or to symbolize the line of its rulers. Since a casting circle requires both physical set-up and a lot of representational preparation, nearly any skill can be made a mandatory part of the preparation. Each time a skill check is failed, one character takes damage equal to the 1d6 per 2 levels of the circle’s Base Encounter Level. This may be a consequence of the danger of the skill check (if someone must erect menhirs in specific positions for the location to be ready, a failed check can be the result of a menhir rolling onto someone from incorrect engineering of its placement). Alternatively since the characters are now beginning to make the first connections to the primal energy that will power their circle, a failed check could result in an actual blast of mystic energy (of an energy type appropriate to the end-goal of the casting circle of the location, or a randomly determined type as the primal energy coalesces in uncontrolled backlash).

It doesn’t matter how often the PCs fail the skill checks, as long as each check is eventually made successfully at least once.

Circle Work “We have to go deeper.”

The actual circle work takes a number of hours equal to the level of the effect the casting circle is designed to create. Any interruption of that time longer than a minute requires the time to be restarted, but no materials are lost, and the location does not have to be re-prepared. If the spell being created has costly materials or similar requirements those must be provided… or the circle work becomes Much more difficult as it adds to the number of tests that must be passed.

If the spell being created by the ritual requires expensive materials not provided, the circle workers must take on additional tests to draw additional energy to make u for the lack. They must face enough additional tests for the treasure value of the encounters the tests comprise to match the value of missing materials, or twice as many tests (whichever total is lower). Each test lasts no more than ten rounds, after which the GM determines if the test was successful, or not. There are three kinds of tests—combat, skill challenge, and trap. Each type of challenge has specific conditions for success.

Combat: Select a single foe of the appropriate base Encounter Level -2, that does not have any mode of movement the Pc does not have. The two fight in a featureless 40-foot cube (though the PC doesn’t actually move from their location, they seem to during this combat). To be successful, the circle worker must do more damage to the combatant than the combat does to them, OR the combatant must be defeated or made helpless. If unsuccessful, the circle worker just has to contend with the damage of the combat.

Skill Challenge: Select a skilled NPC of the appropriate Base Encounter Level -2. Each round the NPC and the PC make one opposed skill check.

The NPC selects the first opposed check, and the Pc the second, and they then alternate. Neither can choose the same skill twice (though they can choose a skill the other has already selected once).

To be successful, the circle worker must win more than half of the opposed checks. If unsuccessful, the take damage equal to their level for every skill check short of success they were.

Trap: Select a trap of the appropriate Base Encounter Level -2 that can be disarmed or bypassed using skills the PC has invested in. To be successful, the trap must be disarmed or bypassed. If unsuccessful, the trap affects the circle worker at the end of the time. If the characters are all successful, the casting circle moves on to the cost, and is then complete. If not, they must face additional challenges until they have a number of successes equal to the number of circle workers. Circle workers may volunteer to take on the additional challenges, but no circle worker can take on a third until all have taken on two, and so on. If no one volunteers, the additional tests are assigned randomly (though again, no one takes a third or subsequent additional tests until everyone has taken at least one).


“Snakes! Why did it have to be snakes?” Circle Work is a struggle between those who are trying to tease extra power out of the universe, and the natural order which keeps that energy locked away. As the circle forms, it creates a kind of demiplane—a quasi-real place where the energy for the circle work gathers until the ritual is over.

The circle workers remain exposed to the material plane, and can be attacked and damaged by things in it. But they are also exposed to the temporary demiplane, and things can form out of that energy that can impact (and be impacted by) one or more circle workers without impacting the rest of the location.

These interactions are referred to as “tests.” There is no true intelligence behind these tests—just the subconscious minds of the participants reacting to the sense of threat and wrongness of stealing energy from the universe, and the mystic power they call upon using those impulses to form potential stumbling blocks. Only by overcoming these tests can the circle works complete their ritual and access the energy needed for their spell effect.

Normally circle work requires the workers pass a number of tests equal to the number of participants. Each test is a single encounter of a level equal to the circle’s Base Encounter Level -2. These can be combats (normally against some kind of outsider, such as an inevitable, genie, or elemental, but can take any form), traps, or even opposed skill checks for metaphysical debates. The PCs cannot interact with each other’s tests – each test exists only for the circle worker acing it – but Can assist each other by interacting only with each other (casting spells, making aid another checks, and so on). Since each circle worker must face one test, you can run them simultaneously to prevent any player from having to sit around and wait for everyone else to be done. If the casting circle is being used to restore an incapacitated creature (such as raising the dead, turning a petrified creature back to flesh, and so on), it must be present. However, their spirit is also summoned by the power of the circle, allowing them to participate in the circle work as if alive and not suffering whatever affliction the casting circle will remove. (Being dead or cursed to eternal sleep is enough of a bummer as a player, they might as well get to try to help fix the problem.)

As long as the circle workers keep taking on tests, they can keep working toward completing the circle work. However, if one of them gives up, refuses to go on, or is knocked out or killed, the casting circle ends, and cannot be attempted again for 1-7 days.

The Cost

You don’t get to call upon energies from the universe without paying a price. There is a backlash of energies that must be absorbed by one or more member of the casting circle. This is the very last casting event, occurring just before the circle work ends. No checks are needed afterward, and even if the consequences of the backlash take out a member of the casting circle, that does not prevent successful circle work from being completed.

The backlash is normally an evocation spell of the same level as the spell being created with the circle work, with a caster level equal to the minimum needed to cast that spell. It targets just one member of the casting circle—even if the spell has an area or normally affects multiple targets.

The backlash is only semi-real, existing in the demiplane that briefly is created by the circle work, and the full brunt of its destruction of bourne by just one member of the circle. The GM can pick a spell that seems thematically appropriate to the casting circle’s goals, or determine the spell at random. A full 75% of the time the backlash spell is from the same spell list as the spell being created.

A single member of the casting circle can take the role of sacrifice once the circle work reaches the point of backlash, in which case they automatically take the backlash spell. They can make saving throws as normal, but SR does not apply (the circle member has effectively chosen to lower SR by taking part in the circle work), and any attack roll needed by the spell is considered to be a success.

If multiple members of the circle choose to take on the role of sacrifice, they are all struck by the backlash spell, but the effects as lessened. For every doubling of the number of targets (2, 4, 8, and so on) taking the role of sacrifice, the spell level of the backlash spell is reduced by 1. This if the casting circle has 6 members and is trying to create a 5th level spell effect, a single sacrifice takes a 5th level spell as backlash, but if 2 members act as sacrifice each takes only a 4th-level spell, and if 4 or more do so each takes only a 3rd level spell. The casting level remains the minimum to cast whatever level of spell forms the backlash.

If no one chooses to take on the role of sacrifice, it is determined randomly.


Once the tests are passed and the cost is paid, the casting circle creates the desired spell effect. If the spell effect normally has any chance to not function as desired, the circle workers get to make that check twice and take the better of the two results.

Or the GM can just let it work. The players went to a lot of trouble for this, after all.

Section 15: Copyright Notice

Casting Circles, 5e © 2020, Owen K.C. Stephens; Author: Owen K.C. Stephens. Project manager and Planning: Lj Stephens. Bon Vivant: Stan!

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