Insane Ancestry

You come from a bloodline of powerful sorcerers who have the strange ability to decrease their sanity. Entering an increasingly insane state comes with its benefits and repercussions. Mastering the art of decreasing your sanity when needed can be difficult, but it allows you to boost the potency of your spells and increase your power.

Insanity

At the third level, when you choose this subclass, you gain the power to control your sanity, measured by something called Insanity. Your base Insanity is 0, and it resets to 0 after you complete a Short or Long Rest. When you cast a spell of 1st level or higher, you can choose to either increase or decrease your Insanity by one, or keep it the way it is. Insanity cannot go below 0 or over 9. Insanity grants the following effects:

Your Intelligence ability score is decreased by the amount of Insanity you have, and the modifier changes accordingly. If your Insanity is over 3, you gain Disadvantage on Intelligence and Wisdom ability checks and saving throws. Once your Insanity is 8 or 9, you become truly insane and automatically fail Intelligence and Wisdom ability checks and saving throws. At Insanity 9, you can't maintain Concentration, preventing you from casting certain spells in that state.

You can choose to use Insanity to cast spells. When you do this, you cast the spell as if you were casting it with a spell slot equal to your Insanity, but your Insanity must be equal to or greater than the spell's level. For example, if your Insanity is 6, you can cast Fireball, a 3rd-level spell, with Insanity. You would treat this as if you were casting it with a 6th-level spell slot, but it doesn't expend a spell slot. You must have at least one spell slot remaining for that level to use this, and after casting a spell this way, your Insanity resets to 0.

Insanity Spells

When you reach a Sorcerer level specified in the Insanity Spells table, you thereafter always have the listed spells prepared.

Natural Madness

At the 6th level, a feeling of insanity permanently resides deep inside you, even when your Insanity is at its lowest. This grants you immunity to being charmed and frightened. While your Insanity is 0, you can cast Cantrips at the 1st level using Insanity. This increases to the 2nd level upon reaching level 11, and to the 3rd level upon reaching level 16.

Cognitive Distortion Field

At the 14th level, you can transmit your insanity to other creatures nearby. As a Bonus Action, you can target up to ten creatures in a 40-foot emanation originating from you. Unwilling creatures can choose to make an Intelligence saving throw to resist these effects (Save DC = 8 + your Charisma modifier + your proficiency bonus). You give targets the effects of Insanity for 10 minutes and set their Insanity to 9 immediately. While under these effects, creatures can use Insanity to cast spells and gain the other effects that come with Insanity. This can be used up to 3 times per Long Rest. Until you finish a Long Rest, creatures take 3d6 psychic damage the second time you target them with this, and take 6d6 the third time due to regular brains being unable to handle your innate insanity properly.

Unbound

At the 18th level, you have learned to truly control the powers of insanity. Casting a spell using Insanity no longer decreases it to 0 unless you choose to do so.

When your Insanity is 8 or 9, you gain a flying speed of 40 feet and can hover, and creatures within a 30-foot sphere originating from you must make an Intelligence saving throw every minute they stay within that sphere (Save DC = 8 + your Charisma modifier + your proficiency bonus) or take 8d12 psychic damage. You can choose to protect as many creatures as you want from this power.