Review spell burst damage and concentration saves

[mlenser]

Describe the bug

Spells can burst for a lot of damage, causing quite high DCs for concentration.

Possible solution

Perhaps concentration DCs should be 5+1/4 the damage?

[Marcloure]

Perhaps concentration DCs should be 5+1/4 the damage?

Whether this formula becomes the standard or not, I think the minimum of 10 should be kept. Otherwise, spells and cantrips that deal 1d2 or 1d4 damage, or hordes of kobolds that trigger many saves while dealing 2 or 3 damage, would become auto-pass at some point. Also, although I never used it, you can require a concentration save against environmental phenomena (storms and such), and this kind of save uses a DC equal to the minimum of 10.

[mlenser]

spells and cantrips that deal 1d2 or 1d4 damage, or hordes of kobolds that trigger many saves while dealing 2 or 3 damage, would become auto-pass at some point

Which is likely how it should be as damage at those levels is not meaningfully impactful.

[mlenser]

1 mana

3-36 damage, averaging 19.5.

• ½ damage: Concentration DC is 11-18, averaging 11
• 5+¼ damage: Concentration DC is 5-14, averaging 9

2 mana

6-72 damage, averaging 39.

• ½ damage: Concentration DC is 11-36, averaging 19.5
• 5+¼ damage: Concentration DC is 6-23, averaging 14

3 mana

9-108 damage, averaging 58.5.

• ½ damage: Concentration DC is 11-53, averaging 29.25
• 5+¼ damage: Concentration DC is 7-32, averaging 19

4 mana

12-144 damage, averaging 78.

• ½ damage: Concentration DC is 11-72, averaging 39
• 5+¼ damage: Concentration DC is 8-41, averaging 24.5

5 mana

15-180 damage, averaging 97.5.

• ½ damage: Concentration DC is 11-90, averaging 48.75
• 5+¼ damage: Concentration DC is 8-50, averaging 29.375

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Conclusion

5+¼ damage seems much more bounded to the system than ½ damage is.

[shemetz]

Small problem: dividing damage by 4 is not great. For example, if a dragon breathes fire on you and rolls 105 damage, but you succeeded on your saving throw so it's 52, and you have resistance so it's 26, which means you divide it twice more to get 13 and then 6, and then add it to 5 to get 11. This is a lot of math (though I admit it's not too hard, and also admit that online play handles this).

[mlenser]

Dividing by 4 is like halving and then halving.

Dividing by 5 is arguably harder? You then have to know your multiplication tables or do the math.

[shemetz]

Heh, I was thinking dividing by 5 is easy because you just multiply by 2 and drop a digit. So 26 → 52 → 5. But honestly that's not much better than dividing by 4, so nevermind that.

[mlenser]

We had a discussion starting around here https://discord.com/channels/701706060440010753/709048873351381042/854728700843261993

Proposal:

If you take 25% of your health on a turn, make a SPELLCASTING SKILL check with Difficulty 11 + your spellcasting ability + the mana used to cast the spell. On a failure, you lose oncentration.

Math on concentration threshold and enemy challenge:

It goes up as the enemy challenge goes up. Half casters would have to make fewer concentration checks. This mirrors RAW where half casters have proficiency on Con much more often so they would succeed on cocentration checks more often.

The same is also true for PCs:

[shemetz]

While I think this proposal is good, I want to bring up one thing to keep in mind - if concentration saves are only made when taking a lot of damage in one turn, there's a much lower (often 0) chance of losing concentration due to bleeding, burning, delayed acid damage, damage at the start/end of your turn due to persistent damaging effects, opportunity attacks, and reaction damage. They can be more dangerous when added together, but usually only 0-2 of these will happen in a single turn.

This could mean that spellcasters are less afraid of triggering opportunity attacks, as their concentration will probably not get broken. Particularly at higher levels, when monsters have many actions so the opportunity attack damage is relatively lower.

This would also make Mage Slayer a bit weaker. Currently its two bullet points mean that spellcasters are punished for staying in melee and punished for trying to leave it (due to the OA having a good chance of dropping concentration). This would be a less punishing if casters are confident that the OA won't trigger a concentration check. Though, I don't know if this matters enough to change it.

What I suggest, if this happens, is to slightly lower the value of "damage in future turns". For example, sacrificing some immediate damage to deal extra acid damage at the end of the enemy caster's turn - would be worse if the combined damage is >25% but the split damage is <25% each time.

[mlenser]

The current concentration system (RAW) has some flaws:

• Difficulties can go very high for high amounts of damage. Far beyond bounded accuracy. This is also true in RAW with single target spells. Spells shouldn't be able to 100% end concentration .
• The most optimal way to break concentraion (at least at low levels) is to force multiple concentration saves. Monks, TWF, etc are very good at this. This gets especially pronounced in my system where there are more instances of ongoing damage like Bleeding, Burning, or spells that continue each round. Small waves don't generate concentration checks and neither should miniscule amounts of damage.

So the goals of a change would be to solve those issues. As part of working on this issue I've also discovered some other factors to consider:

• It should be simple.
• Casters shouldn't be SAD. RAW uses Con saves to help pressure casters to invest in Con. Without that, Dex becomes more valuable. This should also be a factor in my system.
• Ideally, it should be easier to concentrate on less powerful spells (lower mana, less spellcasting ability)

The current proposal seems to address all of those instances fairly well. Though I'm still not 100% on going through with it without some more consideration.

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if concentration saves are only made when taking a lot of damage in one turn, there's a much lower (often 0) chance of losing concentration due to bleeding, burning, delayed acid damage, damage at the start/end of your turn due to persistent damaging effects, opportunity attacks, and reaction damage

See point 2 from the issues that I'd like to solve. This is by design.

punished for trying to leave it (due to the OA having a good chance of dropping concentration)

Opportunity attacks do not have a good chance to end concentration.

This would also make Mage Slayer a bit weaker.

Individual options can be adjusted. Though Mage Slayer is not related to opportunity attacks. It would still force the saving throw to be made with disadvantage when you pass the threshold which would be very impactful.

is to slightly lower the value of "damage in future turns".

Damage is damage. There is no consideration for small amounts of big amounts in the current system. I don't think we should adjust damage in future turns if we go through with this change based on that prescendent.

[shemetz]

The current proposal seems to address all of those instances fairly well. Though I'm still not 100% on going through with it without some more consideration.

Are there any other things to consider before going forward?