Fatigue Casting

Many spellcasters in the Iron Kingdoms are will weavers— individuals who rely on their own willpower to form and summon spells rather than memorize them in the traditional way. This effort takes a toll on their bodies and spirits and can leave them exhausted and vulnerable. If you use this spellcasting variant in your campaign, player characters and nonplayer characters replace their spell slots with the rules below.

Each spell has a fatigue cost based on its level. The Fatigue Point Cost table summarizes the cost in fatigue points of each slot from 1st to 9th level. Cantrips do not produce fatigue and therefore do not have a fatigue cost.

Instead of gaining spell slots to cast spells, characters with the Spellcasting feature accumulate fatigue points each time they cast a spell. A character gains fatigue points to create a spell slot of a given level, as indicated in the Fatigue Point Cost table, and then immediately uses that slot to cast a spell. A character cannot exceed his or her fatigue point maximum when doing so. A character can use a higher-level spell slot to cast a spell of a lower level if that spell allows the character to do so and if the character is capable of casting a spell slot of the appropriate level.

Finishing a long rest reduces a spellcaster’s fatigue points to 0.

Spells of 6th level and higher are particularly taxing to cast. A character can use fatigue points to create one slot of each level between 6th level and 9th level but cannot create another slot of the same level until the character finishes a long rest. This includes any spell of 5th level or lower that is cast using a spell slot of 6th level or higher.

The maximum number of fatigue points a character can accumulate is based on that character’s level as a spellcaster, as shown in the Fatigue Point Maximum table. The character’s level also determines the maximum-level spell slot the character can create. A character cannot create a spell slot above this maximum even if that character has enough fatigue points to do so.

Bards, clerics, druids, sorcerers, and wizards use their level to determine their fatigue point maximum; all other classes use half their level instead.

A character can only cast spells the character knows and has prepared normally, as determined by the character’s class.

GOING BEYOND FATIGUE LIMITS

Once per day, a character can attempt to accumulate more fatigue points than the maximum number normally allowed but cannot accumulate additional fatigue points in excess of the character’s Constitution score. To do so, the character must make a Constitution saving throw with a DC of 10 + the number of fatigue points the character wants to accumulate. On a successful save, the character casts the spell. On a failed save, the character cannot cast the spell, the character gains one level of exhaustion, and the character’s turn immediately ends.

UPKEEPING SPELLS

A character who is maintaining a spell with concentration can accumulate 1 fatigue point at the start of the round to make concentration rolls with advantage.

Magic

Spell Level	Point Cost
1	2
2	3
3	5
4	6
5	7
6	9
7	10
8	11
9	13

Fatigue Point Max

Level	Points	Max Spell Slot
1	4	1st
2	6	1st
3	14	2nd
4	17	2nd
5	27	3d
6	32	3d
7	38	4th
8	44	4th
9	57	5th
10	64	5th
11	73	6th
12	73	6th
13	83	7th
14	83	7th
15	94	8th
16	94	8th
17	107	9th
18	114	9th
19	123	9th
20	133	9th