Hellball 「True Dweomer」

9th-level Evocation (Cleric, Druid, Sorcerer, Wizard)

Casting Time: Action

Range: 300 feet

Components: V, S, M (four flawless elemental gems—a diamond, ruby, sapphire, and emerald—each worth 50,000 gp, which the spell consumes)

Duration: Instantaneous

You unleash a strobing, sun-bright sphere of chaotic energy that streaks unerringly to a point you can see within range, detonating into a cataclysmic roar. A 40-foot-radius sphere of absolute devastation erupts, bypassing all cover lower than total cover.

Every creature and unattended object in the area must make a Dexterity saving throw. On a failure, a target takes 220 (40d10) damage, comprised of equal parts acid, fire, lightning, and thunder damage (55 damage of each type). A creature is utterly disintegrated into ash if reduced to 0 hit points by this damage. On a success, a target takes half damage and is not disintegrated.

Additionally, you must succeed on a DC 43 Intelligence (Arcana) check to channel the volatile elemental friction. On a failure, the spell automatically fails, you suffer backlash taking 99 (18d10) psychic damage, the gems violently shatter into worthless dust, and you gain no benefits.

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 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 Hellball ever again.

Casting as a Circle Spell. Casting this as a Circle spell requires a minimum of two secondary casters. 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 two rites of your choice. Rites are cumulative, with each option incorporating the previous effects:

2–5 Casters Rite: Targets cannot benefit from effects that reduce damage such as Resistance, Evasion or similar traits.
6+ Casters Rite: Targets roll their saving throws with Disadvantage.

Each secondary caster must expend a 8+ level spell slot when the spell is cast, otherwise, it automatically fails.