Fatebinding

3rd level necromancy

Casting Time: 1 action Range: 30 feet Components: V Duration: 1 hour
Choose two creatures that you can see. Both creatures must make Charisma saving throws, and they do so with advantage if they are hostile to you. If a creature is charmed by you, it has disadvantage on this saving throw. If both creatures fail their saving throws, then their fates are now bound together.

Whenever one of the creatures takes damage, the other creature takes an identical amount of damage, unless both creatures took damage from the same single source, such as a fireball spell.

Whenever one of the creatures regains hit points, the other creature regains an identical number of hit points, unless both creatures regained hit points from the same single source, such as mass cure wounds.

The two target creatures remain fate-bound for the duration of the spell, even if both targets are on different planes of existence.