Homebrew:Numerology

(OOC: This is an implementation of the Numerology subclass from Tasha's Crucible of Everything Else volume 1)

Base Class: Wizard

To you, the world is a lattice of systems, a complex constructuction of mathematical interactions. Numbers have meaning and power, and the weave of magic that permeates the multiverse is no different.

Some scholars believe that the world’s ley lines are arranged in a mathematical pattern which, if understood, can yield great magical power. In the World of Eberron, the Draconic Prophecy is studied by mages, dragons, and scholars of all kinds. In the intricate markings of the Prophecy manifested across the world, could there be some numeric pattern just waiting to be understood?

The number of creatures nearby, the shape of the room, or even the hour of the day might all be factors that shape the searing flames of burning hands or guide the subtle influence of charm person. Numerologists, sometimes known as math magicians, use divination magic to observe the physical world around them, estimating and calculating potential interactions with the weave. The numbers change with every passing moment, however, forcing a numerologist to plan ahead and think as fast as a lightning bolt.

Mathematician

2nd-level Numerology feature

You gain proficiency in the InvestigationIntelligence (Investigation)skillWhen you look around for clues and make deductions based on those clues, you make an Intelligence (Investigation) check. You might deduce the location of a hidden object, discern from the appearance of a wound what kind of weapon dealt it, or determine the weakest point in a tunnel that could cause it to collapse. Poring through ancient scrolls in search of a hidden fragment of knowledge might also call for an Intelligence (Investigation) check. skill and with one gaming set of your choice.

Additionally, you can accurately judge the distance between any two points you can see, and you have advantage on Intelligence (InvestigationIntelligence (Investigation)skillWhen you look around for clues and make deductions based on those clues, you make an Intelligence (Investigation) check. You might deduce the location of a hidden object, discern from the appearance of a wound what kind of weapon dealt it, or determine the weakest point in a tunnel that could cause it to collapse. Poring through ancient scrolls in search of a hidden fragment of knowledge might also call for an Intelligence (Investigation) check.) checks you make to perform mathematical calculations, numerical estimations, and statistical predictions.

Spell Arithmetic

2nd-level Numerology feature

You can use a bonus action to divine your surroundings and calculate how to optimize your spells. Roll 5d6, your arithmetic dice. Immediately after doing so, you can reroll any number of the dice, though you must use any new rolls. When you cast a spell during any of your subsequent turns, you can combine and spend your arithmetic dice in any of the following ways to augment the spell.

You can apply multiple augmentations to the same casting of a spell, though you can’t use an arithmetic die for more than one at a time. Any unused dice are lost when you augment a spell in this way, use this feature again, or finish a long rest.

You can use this feature a number of times equal to your Intelligence modifier (minimum of once), and you regain all expended uses of it whenever you finish a long rest.

Empowered Pair

If two arithmetic dice show the same number (such as two 1s), you can spend those dice to reroll a number of the spell’s damage dice equal to the number shown on the arithmetic dice. You must use the new damage die rolls.

Fortunate Sum

If the value of two arithmetic dice add up to 7 (such as 1 and 6, or 2 and 5), you can spend those dice to increase your spell save DC and spell attack modifier by 1 for this casting of the spell.

Rising Run

If four arithmetic dice show consecutive numbers (such as 1–2–3–4), you can spend those dice to cast the spell as though with a spell slot one level higher than the one you expend.

Astute Prediction

6th-level Numerology feature

You learn the augury spell. It counts as a wizard spell for you, you always have it prepared, it doesn’t count against the number of spells you can prepare each day, and you don’t need to have it in your spellbook to cast it as a ritual.

Geometrist

6th-level Numerology feature

You can reshape your spells by altering their formulas. When you prepare a wizard spell that creates an area of effect in the shape of a cone, cube, cylinder, line, or sphere, you can expend a use of your Spell Arithmetic to change one of those shapes into a different one, as shown in the Shape Conversions table. You can apply the changes whenever you cast the spell until you finish your next long rest.

When dividing measurements, round up to the nearest 5 feet. See chapter 10 of the Player’s Handbook for the rules of areas of effect shapes.

Shape Conversions

Original Shape	New Shape	New Shape Measurements
Cone	Line	Length = Cone Size × 3, Width = 5 feet
	Cube	Size = Cone Size ÷ 2
	Sphere	Radius = Cone Size ÷ 2
Cube	Line	Length = Cube Size × 6, Width = 5 feet
	Cone	Size = Cube Size × 2
	Sphere	Radius = Cube Size × 2
Cylinder or Sphere	Line	Length = Radius × 6, Width = 5 feet
	Cone	Size = Redius × 2
	Cube	Size = Radius
Line	Cone	Size = Length ÷ 3
	Cube	Size = Length ÷ 6
	Sphere	Radius = Length ÷ 6

If you create an area of effect centered on yourself, you can exclude yourself from it. These conversions otherwise don’t affect a spell’s range, For example, if you cast lightning bolt as a sphere, the sphere still originates from you, and if you cast the shatter spell as a line, the line still originates from a point within range.

Advanced Arithmetic

10th-level Numerology feature

You can reroll your arithmetic dice twice, rather than once, whenever you use your Spell Arithmetic.

Grand Alignment

14th-level Numerology feature

You gain the following additional combination options for your Spell Arithmetic.

Perfect Set

You can spend five arithmetic dice that all show the same number (such as five 5s) to deal maximum damage with the spell instead of rolling damage dice.

Heightened Run

You can spend five arithmetic dice that show consecutive numbers (such as 1–2–3–4–5) to choose one of the spell’s targets and force it to make its first saving throw against the spell with disadvantage.