Enialeigh's Void Arrow (Arteria)

You fire a dark arrow infused with necrotic energy, aiming at the heart of your target. Make a ranged attack against one creature within range. On a hit, the creature takes 10d8 necrotic damage and must make a Constitution saving throw. On a failed save, the target's hit point maximum is reduced by an amount equal to the necrotic damage dealt. The reduction lasts until the target finishes a long rest.

If the creature is reduced to 0 hit points by this arrow, its soul is consumed by the void, and it cannot be resurrected by any means short of a True Resurrection or a Wish spell.

At Higher Levels: When you cast this spell using a spell slot of 8th level or higher, the damage increases by 2d8 for each slot level above 7th.