Vitality Core

Fourth of Ars Conserva (The Art of Conservation) - Spell Series

A spectral gem forms above the willing creature, tethered to their life force. They lose half their current hit points (rounded down), and the gem gains hit points equal to the amount lost. Their hit point maximum becomes equal to their remaining hit points for the duration. They can’t regain hit points or gain temporary hit points by any means while this spell is active.

Any damage they would take is transferred to the gem instead. The gem cannot be directly targeted or affected by spells, attacks, or effects. If the gem reaches 0 hit points, the component is destroyed and the spell ends.

Each time you cast a cantrip that hits a creature or causes a creature to fail a saving throw, the gem regains 15 hit points. The gem can exceed its original hit point total.

If you are concentrating on another spell when you cast this spell, it fails and the spell slot is wasted. Once active, this spell immediately ends if you cast a spell of 2nd level or higher.