D&D 5E Experimental Concentration Spell Stacking Houserule

[Li Shenron]

It's too complicated for my tastes... but it's understandable since you seem to have multiple aspects you want to change:

1- you want to allow maintaining more than one concentration spell at the same time
2- you want some spells not to be disrupted by taking damage
3- you want some spells to be more restricted than others to maintain
4- you want the ability to scale with level

That's quite a lot of purposes to cover. If I were you, I would start experimenting with a house rule that takes care of only 1 or 2 of these, without pretending to finalize a "system" that covers everything. It's your game after all, so it only has to work for your group, not to be a universal system.

YMMV but I wrote those 4 points in order as I would personally consider them from the most important to the least, so I would start addressing point 1 by simply allowing 2 concentration spells at once, but limited to lower levels. So it could read like "You can maintain concentration on maximum 2 spells at the same time rather than 1, if both spells are of a level lower than the maximum you can cast." Maybe I would think of a real-time cost, although I don't know at the moment what cost would be appropriate.

Secondarily, I would address point 2 of "focus" instead of "concentration". I think you might be thinking that some spells aren't that powerful to justify being concentration, but you still don't want them to be stackable freely. If that's the case, it's enough that you make your list of these spells, say that concentration limitations apply but checks aren't needed. But I don't think you need to go farther and allow more stacking of these, keeping them together with other concentration spells under the same limit is OK. That's why I would avoid thinking of point 3 for the time being.

And I would also avoid worrying about point 4: make a house rule that works for your current group level, worry later about whether at higher levels you should grant even more freedom.

 

[humble minion]

I can't help but think that any feat that let you concentrate on two spells at once without very significant cost would be pretty much a must-take for any full caster, at least once they'd maxed out their spellcasting stat. And any feat that is a must-have is probably overpowered. Maybe you can concentrate on two spells but you need to use your bonus action (maybe also your reaction as well) every round of the spell duration to do so? Even that might be too powerful, to be honest.

 

[Fanaelialae]

I also think it looks a bit complex, but could work.

I have a house rule myself for allowing multiple concentration.

If you cast a concentration spell while already concentrating on a spell, you must make an immediate DC 10 concentration save or lose the spells you are concentrating on (but not the one you are casting). You have a -5 penalty on all concentration saves for each spell, beyond the first, that you are concentrating on.

I also have a feat that can circumvent this penalty under certain circumstances.

Focused Arcana

• You can maintain concentration on two spells simultaneously without penalty provided that the sum of the spell levels does not exceed the highest spell level you can cast. For example, a 5th level caster could concentrate on a 1st and a 2nd level spell without penalty, but could not do so with two 2nd level spells. Regardless of your maximum spell level, you can always concentrate on a second cantrip without penalty (as though it were a zero level spell).
• You do not automatically lose concentration when you become unconscious.
• You gain two cantrips that require concentration.

I've had at least one caster take that feat, and didn't find that it caused any issues.

 

[DND_Reborn]

i considered such a rule as well, but I also want to address the notion that some “concentration” spells I don’t think need to be disrupted, so i went with the focus concept to differentiate them

I would just remove the concentration tag from those spells then. Otherwise seems too fiddly to me, but if it works for you cool.

 

[Quartz]

I think the system as presented in the OP is too complex. However the use of Proficiency Bonus is nice. I'd just simplify it as a Feat for higher level PCs.

Feat: Spell Concentration

You may concentrate on a number of spells equal to half your Proficiency Bonus, rounded down, plus one cantrip.

 

[MostlyHarmless42]

Your system seems complex but I'm interested in hearing how it works for your group. I'm guessing it's too OP.

Here's a simpler idea: create a feat called Dual Caster that allows them to cast two concentration spells but only control one per turn. So if they cast two flaming spheres they can only move one one their turn. You could also rule that they can't cast a cantrip that turn if they control/change the effects of one of their two concentration spells. This seems like it would be simpler and more balanced to me.

The problem with making it a feat is that it would undoubtably become a feat tax due to being too universally good for every spellcaster not to take. I'd suggest keeping it to either a varient ruling, or in the realm of magic items.

Something I've consider in the past is allow a second concentration slot somewhere between 5th level and 11th level. Under NO circumstances do I think a player should ever get above two slots, and honestly it's something only higher level mages should be able to do.

Also keep in mind whatever ruleset you give to the players needs to apply to NPCs, whom arguably need it more than players. An archmage fight is trivialized largely due to concentration.

Another option I've tried is giving magic items limited ability to do a second concentration slot using either the spells on the item (i.e. a staff or wand), or a thematically appropriate spell options, like a fire item working with fire spells, or a specific spell school, etc. I still rule that it's one check and every spell is lost on failure though.

 

[Guest 6801328]

FWIW we just allow multiple concentration spells at one time. BUT.... our DC min is 15, not 10, and when you have to make a concentration check you make separate checks for every spell you have active. If you fail ANY of the checks, ALL the spells active go down.

As such, we have PCs sometimes concentrating on two spells, very rarely do we see more than that.

The higher DC is an improvement.

By itself, "fail any concentration check and lose all spells" is insufficiently risky to make it an interesting trade-off. If you're deciding between casting a second concentration spell, and waiting until you lose concentration on the first one to cast the second one...which both costs an action and has probably missed most fo the fight...why wouldn't you go with double concentration? There are edge cases, sure, but in general it's a better strategy to stack.

In my mind it should be the other way around: the times when it's worth the risk to stack concentration should be the edge cases.

 

[Guest 6801328]

The problem with making it a feat is that it would undoubtably become a feat tax due to being too universally good for every spellcaster not to take.

Another reason it should be very risky to use. Powerful when it works, but so risky that it nets out to being a power boost appropriate to a feat. (As per my previous post.)

 

[DeviousQuail]

Perhaps some irreducible damage as a tradeoff similar to Overchannel. It could be one roll when you cast your second spell or a smaller amount of damage each turn. I'd lean toward damage each turn equal to the combined spell levels of the two spells. This damage wouldn't trigger a concentration save.

 

[GlassJaw]

Three things are true:

1. Overall, the concentration mechanic has been a great addition to 5E.
2. Some spells are hurt more than others by requiring concentration and therefore, rarely - if ever - get used.
3. This solution is far too complex and wouldn't survive 5 minutes at the table.

I agree that #2 needs to be addressed but it's not in my top 3 or 5 biggest issues with 5E.

I've seen a solution that simply leaves the concentration mechanic intact but removes the check for certain spells (like True Strike and the "smite" spells). This helps caster characters that enter melee who are more apt to take damage and therefore have to make more concentration checks. Removing those checks helps but doesn't solve the biggest problem of making some spells more attractive to use.

Ray of Enfeeblement is a big offender: not only does is it a Concentration spell, it requires an attack roll and the target can attempt a save every turn. You could remove concentration and instantly make it more attractive.

This is what I do first: go through the spells and remove concentration from spells that meet one or more of the following criteria:

• Require an attack roll (Ray of Enfeeblement, Witch Bolt)
• Require an action to continue to use (Witch Bolt)
• Allow a save every round (Ray of Enfeeblement)
• Require the caster to be in melee (Vampiric Touch, smite spells)
• Rarely get used

You could even go one step further and take a thematic approach, differentiating between spells that place an adverse effect on a target (like blinding smite) and a spell effect that the caster need to "upkeep" (like wall of force). Care must be taken with this approach because you can easily get yourself into a pickle (like bane vs. bless).

I don't think anyone would argue that concentration should be removed from Bless. But since Bane requires a save and isn't used as frequently, it makes more sense for concentration to be removed.