D&D 5E (2024) Circle Casting is gonna break a lot of games

[BenjaminPey]

I don't see this breaking too many things at a quick glance, though I'm not an optimizer by any means and I'm sure there will be some corner cases.
The main thing is that the casters must all maintain concentration up until the end of the turn of the last caster. That's a lot of time for the ennemy to react and break it. Legendary actions will be clutch, here.
The second thing is all usual limitations apply and most of the spells will still require that you see the target.
The third thing is you can only select one option for a spell. So your fireball either has super long range or is super wide, not both. I don't see many BBEG being murdered at a distance with that. He still is well-protected behind his castle's walls.
The fourth thing is you must have Pact Magic or the Spellcasting feature, and some options require to expend a spell slot.
The last thing is there's a very simple house rule I can see many tables adopt just in case: you only can circle cast the spells which have circle casting options (there are some in this book).

 

[Whizbang Dustyboots]

And it lets PCs in on something that has traditionally been everywhere in most D&D stories (at least in mine) - the group of "Cultists" or "Wizards" that work together to do a "Big" spell!

I would have preferred if the system let the spellcasters cast spells they couldn't otherwise do, possibly including epic spells (which fits in nicely with the Forgotten Realms).

So you could have a group of lower level wizards get together to cast Gate or some other spell they couldn't cast normally, as part of their big sinister plan, or the evil archmage gathers their apprentices (and has reason to have apprentices, which is nice) to be able to cast a level 10 spell and really unleash hell.

Sharing concentration and adding knobs to turn on spells that didn't previously exist feels way too ripe for abuse.

 

[UngeheuerLich]

Going down the list of the new Circle Casting options in Heroes of Faerun and boy, is it going to have an effect. The below video explains each in detail. For example, anyone with the spellcasting or pact trait can be a secondary spell caster. That means a level 1 caster dip, magic initiate feat

Not magic initiate feat. You don't get the spellcasting or pact mafic feature.

, or other minor thing that gives a spellcasting ability means you can help augment other casters. One of the things you can do is share concentration.

Yes, this is nice if you prebuff.
So not everyone has to be a full spellcaster.

So level 9 wizard casts a concentration spell with a level 8 fighter/1 wizard. The f/w takes on the concentration aspect, allowing the spell to take effect and last while the level 9 wizard casts another one the next turn on their own. And that's just the start of potential game breaking stuff.

Yes. Nice thing.

Or you can increase an AoE by 20 feet. An example given is increasing the width of a lightning bolt from 5 ft wide to 25 feet wide. Again, that level 1 dip PC can help do this.

Both spending a magic action and the caster needs to concentrate on the spell until everyone joins in.

 

[mellored]

I would have preferred if the system let the spellcasters cast spells they couldn't otherwise do, possibly including epic spells (which fits in nicely with the Forgotten Realms).

So you could have a group of lower level wizards get together to cast Gate or some other spell they couldn't cast normally, as part of their big sinister plan, or the evil archmage gathers their apprentices (and has reason to have apprentices, which is nice) to be able to cast a level 10 spell and really unleash hell.

Sharing concentration and adding knobs to turn on spells that didn't previously exist feels way too ripe for abuse.

there are a few circles specific spells in the book that really work well for "unleashing hell" by getting a bunch of apprentices.

 

[Zardnaar]

Its not going to do much. The really nutty stuff requires a lot of casters.

And its a subsystem that's optional, casuals probably wont see it, care about it or use it.

Its probably about as broken as previous attempts at circle magic, epic magic etc. Basically you probably wont see it.

 

[FitzTheRuke]

I would have preferred if the system let the spellcasters cast spells they couldn't otherwise do, possibly including epic spells (which fits in nicely with the Forgotten Realms).

So you could have a group of lower level wizards get together to cast Gate or some other spell they couldn't cast normally, as part of their big sinister plan, or the evil archmage gathers their apprentices (and has reason to have apprentices, which is nice) to be able to cast a level 10 spell and really unleash hell.

Sharing concentration and adding knobs to turn on spells that didn't previously exist feels way too ripe for abuse.

You are right. A bespoke "10th level spell" system (where everything is a multi-caster ritual that requires rare material components and speciality research) would suit the fiction significantly better than this.

 

[AlViking]

That actually depends on the Circle benefit being attempted.

Augment, Distribute, and Safeguard don't require secondary casters expend a slot.

Expand and Prolong require expending a slot, but it doesn't list a minimum slot requirement.

Only Supplant requires each secondary caster to expend an equal or greater slot.

If I were to use this, I would make that true for all the options. But I misread it - I thought it applied to all. That's what I get for reading it on my phone.

 

[UngainlyTitan]

I don't know, I'm not an optimizer at all, and even I can see how downing a bbeg from up to a mile away can be abused or problematic. Or how much power increase there is by turning a 5 ft wide lightning bolt into a 25 ft wide bolt by just adding one secondary caster

Targeting something a mile away requires 6 secondary casters. 1 per 1000 feet there are 5,280 feet in mile.
A lot of the scenarios I have seen are very white room and have some assumptions that I have doubts about in actual practise.
My inclination at this point would be to allow it but with the caveat that if it becomes a problem I will revisit

Going down the list of the new Circle Casting options in Heroes of Faerun and boy, is it going to have an effect. The below video explains each in detail. For example, anyone with the spellcasting or pact trait can be a secondary spell caster. That means a level 1 caster dip, magic initiate feat, or other minor thing that gives a spellcasting ability means you can help augment other casters. One of the things you can do is share concentration.

So level 9 wizard casts a concentration spell with a level 8 fighter/1 wizard. The f/w takes on the concentration aspect, allowing the spell to take effect and last while the level 9 wizard casts another one the next turn on their own. And that's just the start of potential game breaking stuff.

In this case, two characters are taking a magic action in the first round and if damaged must make a concentration check, unless they win initiative or the secondary caster uses delay to act after the primary. Either way the fighter is not attacking in the first round. Then unless the fighter is going to run away and hide they are going to be hit a lot taking concentration saves each time to keep that spell running.

Or you can increase an AoE by 20 feet. An example given is increasing the width of a lightning bolt from 5 ft wide to 25 feet wide. Again, that level 1 dip PC can help do this.

Nope, it is 10 feet per secondary caster and a spell slot per secondary caster. So the 25' lightning bolt needs 2 secondary casters and 2 extra spell slots to cast that extra wide bolt. Which is better, 2 greases and a web or 3 casters doing a 25' lightning bolt? Or Conjure Animals, Fear and Hypnotic Pattern, instead?

I also think I would not allow spontaneous no prep circle casting unless they had planned and rehearsed it beforehand.
I am not saying it is not powerful but there I think that there are individual spells more powerful with less effort and am reluctant to condemn it outright.

 

[billd91]

If you aren't sure about using this as a DM but your players want to, just suggest this scenario to them and ask if they still want it:

Suppose a trio of cultists circle cast a banishment or heat metal on your heaviest hitter of a PC then use distribute to distribute concentration. You still want us to use circle casting?

And then see how they feel.

 

[Sacrosanct]

I don't see this breaking too many things at a quick glance, though I'm not an optimizer by any means and I'm sure there will be some corner cases.
The main thing is that the casters must all maintain concentration up until the end of the turn of the last caster. That's a lot of time for the ennemy to react and break it. Legendary actions will be clutch, here.
The second thing is all usual limitations apply and most of the spells will still require that you see the target.
The third thing is you can only select one option for a spell. So your fireball either has super long range or is super wide, not both. I don't see many BBEG being murdered at a distance with that. He still is well-protected behind his castle's walls.
The fourth thing is you must have Pact Magic or the Spellcasting feature, and some options require to expend a spell slot.
The last thing is there's a very simple house rule I can see many tables adopt just in case: you only can circle cast the spells which have circle casting options (there are some in this book).

Let's look at the first official campaign, don't even need to look further. At the very start. A blue dragon attacks Greenrest. A dragon has a fly speed of 80 feet (dash 160). A 1st level party of only two caster (very common) can cast Tasha's Hideous Laughter at 1000 feet out. 6 turns before the dragon can even get there. There is still a very real chance the dragon fails it's save. And falls hundreds of feet to the ground. (admittedly this would be freaking hilarious).

That's just one example. Extending the range of a spell by 1000 feet is huge. I see a lot of "well, both casters have to maintain concentration until the spell goes off." in this thread. That's totally moot if the enemy is several rounds away before they can even do anything to you.