Eternal Seal「True Dweomer」

9th-level Abjuration (Wizard)

• Casting Time: 1 action or Circle Magic Option
• Range: 120 feet
• Components: V, S, M (a flawless diamond sphere worth at least 250,000 gp, which the spell consumes, and a drop of blood from a deity, primordial, or unique planar ruler)
• Duration: Special (see text)

You target one creature you can see within range. The target is instantly hit by an inescapable crushing vacuum. There is no saving throw against the initial casting; the target automatically gains +3 Exhaustion Levels. At the end of each of its turns, the afflicted target must make a Charisma saving throw. On a failed save, the vacuum tightens, and the target immediately gains + 1 Exhaustion Level. When the target accumulates a total of 6 levels of Exhaustion, it does not die; instead, the crushing vacuum collapses into a flawless, indestructible crystalline sigil that permanently binds the creature inside an isolated, microscopic extradimensional void. This absolute imprisonment effect is entirely permanent and lasts for 100 years, during which the target remains completely frozen in stasis and cannot be freed by any mortal means. This effect cannot be affected by Wish. This effects ignores immunity.  If the target is reduced to 0 hit points by any other means while under the turn-by-turn effect of this spell, it is instantly disintegrated into nothingness, its soul is shredded, and it cannot be resurrected by any means short of a True Dweomer cast specifically to undo the effect.

Conversely, if the target succeeds on three of these saving, the spell ends, the containment collapses, and the target stabilizes—retaining whatever current levels of exhaustion it accumulated during the process.

Additionally, you must succeed on a DC 70 Intelligence (Arcana) check to decipher the foundational science of high-magic spellcraft and anchor the cataclysmic energy. As part of this check, you automatically suffer backlash, taking 99 (18d10) psychic damage from the immense, reality-shattering destruction and you gain +1 Exhaustion Level. If the check fails, the spell fails completely, the 250,000 gp diamond sphere shatters into worthless dust, and you take an additional +2 Exhaustion Levels.  This effects ignores 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 Eternal Seal ever again.

Casting as a Circle Spell. Casting this as a Circle spell requires a minimum of 5 secondary casters. The spell's range increases to 1 mile, and its casting time changes to 1 hour. Every caster gains 1 level of Exhaustion per participant (to a maximum of 3 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 Eternal Seal as a Circle spell.