Mana Short 「True Dweomer」

9th-level Abjuration ( Sorcerer, Warlock, Wizard)

• Casting Time: 1 action
• Range: 300 feet
• Components: V, S, M (an Ioun Stone of Absorption, which cracks and is permanently destroyed if the spell takes effect)
• Duration: Concentration, up to 1 minute

You focus a violent mystical vacuum into the magical essence of a creature with the Spellcasting trait that you can see within range, using your material component as a conduit. The target must immediately make a Charisma saving throw.

On a failed save, the suppression becomes immediate: the target instantly expends all of its available spell slots of 1st through 8th level as if they had already been used. The target retains its 9th-level spell slots during this time.

At the end of each of its turns, the afflicted target must repeat the Charisma saving throw. If the target succeeds on three of these saves, the spell ends and its regular slots are restored. If the target fails three of these saves, the slot expenditure becomes permanent, the component shatters into worthless dust, and the spell ends. On a successful save against the initial casting, the target is completely unaffected and the component is preserved.

Additionally, you must succeed on a DC 50 Intelligence (Arcana) check to decipher the foundational science of high-magic spellcraft and anchor the arcane void. As part of this check, you automatically suffer backlash taking 99 (18d10) psychic damage from the immense feedback. If the check fails, the spell fails completely, the component shatters regardless, you take an extra 99 (18d10) force damage, and you gain no benefits. After this spell is cast, you gain 1 level of Exhaustion. Both effects ignore resistance and immunity. While you have Exhaustion levels gained from this spell, finishing a Long Rest neither restores lost Hit Points nor reduces your Exhaustion level.

True Dweomer. Magic of high power automatically fails the very first time you cast this type of spell, requiring you to expend twice the amount of time and resources to effectively complete this magic of high power at least once. In doing so, and successfully casting a true dweomer spell, you attract instant cosmic scrutiny. The severe metaphysical friction of shaping this forbidden magic weakens your form. After casting this spell, each time you cast a spell until you finish a Long Rest, you take 1d10 necrotic damage per level of that spell. This damage ignores resistance and immunity. Furthermore, your Constitution score becomes 3 for 2d4 days while simultaneously your Intelligence score becomes 3 for one month. For each day you spend resting and doing nothing more than light activity, your remaining recovery time for your Constitution score decreases by 2 days. Finally, there is a 33 percent chance that you are unable to cast Mana Short ever again.

Casting as a Circle Spell. Casting this as a Circle spell requires a minimum of 3 secondary casters. The spell's range increases to 1 mile, and its duration increases to until dispelled (no Concentration required). Every caster gains 1 level of Exhaustion per participant (to a maximum of 4 levels from this rite). When the spell is cast, each secondary caster must expend an 9+ spell slot; otherwise, the spell fails.

The number of secondary casters also determines the spell's modified effects, as shown in the table below. The spell ends early if any caster who participated in this casting contributes to another casting of Mana Short as a Circle spell.