Ioulaum’s Longevity 「True Dweomer」

• Casting Time: 24 hours or Circle Spell option
• Range: 2 miles (10,560 feet)
• Components: V, S, M (684,000 gp, which the spell consumes)
• Duration: Instantaneous

You target a point you can see within range. A translucent emerald sphere erupts in a 120-foot radius, bypassing all cover lower than total cover. When you cast this spell, you can designate creatures to be unaffected by it. Each creature in the area must make a Constitution saving throw. On a failure, a target takes 99 (18d10) force or necrotic damage (your choice) and is disintegrated into ash if reduced to 0 hit points. On a success, it takes half damage and is not disintegrated. For every living creature disintegrated, your natural lifespan extends by 1 year. This extension increases your maximum life expectancy by up to 50 percent. Additionally, you do not suffer the physical frailty of old age, though you still die when your time comes.

Additionally, you must succeed on a DC 45 Intelligence (Arcana) check to decipher the foundational science of high-magic spellcraft and anchor the stolen life force. On a failure, you suffer backlash as the spell automatically fails and you take 99 (18d10) psychic damage, gain no lifespan extension, and the material components are wasted. After this spell is cast, you gain 1 level of Exhaustion. This effect ignores 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 spells, 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 uccessfully 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 Ioulaum’s Longevity ever again.

Casting as a Circle Spell. Casting this as a Circle spell requires a minimum of two secondary casters. If the spell is cast as a Circle spell, its duration becomes 1 hour. Also. every caster in the circle gains 1 level of Exhaustion per assistant participating (to a maximum of 4 levels from this rite).
When you cast the spell, you perform one of three tires of your choice. Rites are cumulative, with each option incorporating the previous effects:

• 2–5 Casters Rite: Maximum lifespan extension bypasses racial limits, capped at an additional 99 years per caster.
• 6–8 Casters Rite: The additional lifespan extension cap increases to 999 years per caster.
• 9 Casters Rite: The lifespan extension cap is removed entirely, and targets roll saves with Disadvantage.

Each secondary caster must expend a 9th-level spell slot when the spell is cast, otherwise, it automatically fails.