Spellcasting with Mana Points
Does anyone find "spell slots" remotely sensible? Instead of D&D 5e’s spell slots, we will be using the D&D 5e DMG variant system for “Spell Points” with a few adaptations, naming the fuel for the magic "mana" and the points pool "Mana Points" (MP) ~ alternately "Magic Points".
Versatility & Sensibility
Spellcasting pulls from a list of spell powers known to the caster and draws power from the pool of MP to fuel the effect. Additional MP points can be spent to cast stronger effects. This builds on the D&D 5e standard rules' "slot" concept, but rather than using the DMG's non-uniform SP cost progression (where that math makes no sense), the MP casting cost is simply the level of the spell "slot" +1. (Explanation for this at the bottom of this guide.)
Spellcasting Modifier
This remains the same as in the base rules. Each class specifies which attribute modifier is used (usually INT, WIS or CHA) and then Proficiency is always added (knowing a spell always means proficiency). The Spellcasting modifier is added to a spell’s d20 attack and the Saving Throw DC of 8.
Limitations
Mana Limit
Spellcasters cannot spend more MP to power single spell than the MP cost of the highest level spell they can learn (unless specifically noted otherwise in the spell description.)
Example: Beginner caster Alice with only 1st level spells cannot spend more than 2 MP per spell, but experienced caster Brunhilda, able to cast 4th level spells, can spend up to 5 MP on a single spell.
Cooldown
To repeat a casting of the same exact spell requires time to reset one’s mind. Unless otherwise specified on a spell's description, this interval will be either (casting time) or (1 round per base spell level) – whichever longer.
Examples: 1st level spells can be cast every round, 2nd level every other round, 3rd level must skip 2 rounds between, etc.
High Level Limitations
Due to the strength of magic use at 6th level of power and higher (use of 7MP or greater in a single spell casting), a long rest is required before expending that level of MP again.
Example: A 14th level Cleric would be able to cast only once using the slot for 7th level (8MP) until taking a long rest. (This means use of that 8MP slot not only for 7th level spells like Fire Storm, but also if casting a lower level spell using those 8MP to boost the spell effects - like casting Flame Strike (5th level) to get the extra 2d6 damage from the two additional "slot" levels.)
Regaining Mana
Resting
A long rest will fully replenish your MP pool.
While taking a short rest, you may choose to spend one of your remaining Hit Dice to restore a number of MP equal to your Spellcasting modifier.
(In place of using that Hit Die for restoring Hit Points).
Other Mana Sources
Some campaigns may choose to add magic items such as Mana Potions (to work like Healing Potions) or equipment (or familiars) that regenerate MP over time or provide additional stores from which to draw MP.
Table for Full Casters
(Cleric, Druid, Sorcerer, Wizard)
| Level | MP Pool | Max Level (Slot) | Max MP for Single Spell |
|---|---|---|---|
| 1 | 4 | 1st | 2MP |
| 2 | 6 | ||
| 3 | 14 | 2nd | 3MP |
| 4 | 17 | ||
| 5 | 25 | 3rd | 4MP |
| 6 | 29 | ||
| 7 | 34 | 4th | 5MP |
| 8 | 39 | ||
| 9 | 50 | 5th | 6MP |
| 10 | 56 | ||
| 11 | 63 | 6th | Only 1 6th until long rest |
| 12 | 63 | (only 1 cast using 7MP) | |
| 13 | 71 | 7th | Only 1 7th until long rest |
| 14 | 71 | (1 7MP cast + 1 8MP cast) | |
| 15 | 80 | 8th | Only 1 8th until long rest |
| 16 | 80 | (One each: 8, 9 & 10MP) | |
| 17 | 90 | 9th | Only 1 9th until long rest |
| 18 | 96 | (1 each: 8, 9, 10 & 11MP) | |
| 19 | 101 | ||
| 20 | 111 | Add one 6th slot per rest. |
Other Casters
- Warlocks apply their own special rules.
- Paladins and Rangers follow the table for full casters using half their level (round up).
- Minor casters like Arcane Knights use the table for full casters using this formula:
[My Level 3-9] use (My Level - 1) / 2 (round down)
[My Level 10-20] use (My Level + 2) / 3 (round down)
Because these never access 6th level spells, there is no slot limit, but all castings are still limited by the Max MP column.
MP Pool vs. SP Pool
The MP pool increases more slowly than the DMG's listed SP pool. This is due to those pool sizes being derived from the play-balance slot equivalence per level.
(I did not catch this in my first draft of this system - thanks to CoffeeSorceror69's version of Spell Points for cluing me in to this!)
Motivation
Why did you say the math makes no sense?
Example: WIS +2 casting Cure Wounds
Let's look at casting 1st level spell Cure Wounds using higher level slots (and assuming a Cleric with a +2 WIS bonus). Other spells would likely be used in time-sensitive contexts (Healing Word, Heal, etc.) so what is the advantage of the slot boost?
Using DMG 5e's SP:
| Slot | Cost | Heal Effect | Average Heal | HP per SP |
|---|---|---|---|---|
| 1st | 2SP | 1d8+2 | 6.5 HP | 3.3 |
| 2nd | 3SP | 2d8+2 | 11 HP | 3.7 |
| 3rd | 5SP | 3d8+2 | 15.5 HP | 3.1 |
| 4th | 6SP | 4d8+2 | 20 HP | 3.3 |
| 5th | 7SP | 5d8+2 | 24.5 HP | 3.5 |
Compare 4th level casting vs. casting 2nd level twice:
- Same casting cost: (6 SP) vs. 2 x (3 SP)
- But HP average healed is 20 vs. 22 (2 x 11)
Using MP system:
| Slot | Cost | Heal Effect | Average Heal | HP per MP |
|---|---|---|---|---|
| 1st | 2MP | 1d8+2 | 6.5 HP | 3.3 |
| 2nd | 3MP | 2d8+2 | 11 HP | 3.7 |
| 3rd | 4MP | 3d8+2 | 15.5 HP | 3.9 |
| 4th | 5MP | 4d8+2 | 20 HP | 4.0 |
| 5th | 6MP | 5d8+2 | 24.5 HP | 4.1 |
The effects are less severe in this case if the caster's WIS bonus was +0, but let's be honest, that is an unlikely scenario. Even with Healing Word this happens - DMG version yielding diminishing returns rather than more potent.