Crystalline Banishment

One creature that you can see within range must succeed on a Charisma saving throw or be be banished to a crystalline prison within An Unknown Plane of Existance. While there, the target has the Incapacitated condition. When the spell ends, the target reappears in the space it left or in the nearest unoccupied space if that space is occupied.

While banished, the creature is trapped in a mirrored crystal sarcophagus within An Unknown Plane of Existance, unable to perceive or be perceived.

Lost Arcana:

• Crystals of Will: For each additional 100 gp worth of crystal consumed during casting, subtract 1 from the creature’s saving throw.

• Overcharge Effect: If the caster sacrifices 10 year of a willing creatures life, the crystal prison lasts 1 year longer, even if concentration ends.

• A willing creature can give their life binding their soul to the crystal used to banish the target indefinitely.

• A Creature that dies binding their soul this way cannot be resurrected by anything short of a wish spell.

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  A creature banished this way cannot be removed from banishment by anything short of a wish spell. 

Using a Higher-Level Spell Slot. You can target 1 additional creature for each spell slot level above 4.

Casting this spell imposes a mental corruption. Immediately after casting, make a DC 15 Charisma saving throw:

At 3 Corruption Points, you gain the Shadowbrand condition:

• You begin manifesting minor Vecnan traits (e.g., withered veins, phantom voices, compulsions to hoard secrets).

• Once per long rest, Vecna may speak directly to you, offering you forbidden knowledge in exchange for acts of betrayal, cruelty, or silence.