Death link

Death link, also known as body sympathy, was an arcane necromantic spell that connected the caster with a target creature in such a way that damage or healing to one also affected the other.

Effects
When cast, the target had to be within 240 yd (220 m) of the caster, but for the duration of the spell, the distance between caster and target did not matter as long as they were both on the same plane of existence. If one of the participants traveled to a different plane, then the link was severed with no ill consequence. For the oldest version of this spell, it was only required that the caster visualize his or her victim.

While linked, any damage suffered or healing bequeathed to one was also transferred to the other. The spell lasted a minimum of two hours and forty minutes; longer for more experienced casters. The target had a chance to resist the magic of this spell or else both participants were locked into the spell&mdash;even the caster could not dispel it prematurely. If the caster was killed, then so was the linked creature, but not vice versa. However, if the target creature had more health than the caster to start with, then it was possible for the caster to die from transferred damage, leaving the victim wounded but alive.

Usage
This spell was sometimes used to inflict torment as revenge on a weaker enemy, but saw more frequent use in preventing treachery during negotiations. It could also be used to heal a comrade that was in a dangerous situation but inaccessible by normal healing means.

Components
Only verbal and somatic components were required to cast this spell. The oldest version of this spell also required the utterance of the target's true name as part of the casting.

History
Death link was recorded in a tome of unknown origin called The Alcaister at least 600 years before it was published in Volo's Guide to All Things Magical when it became generally known to the magical community, although it was uncommon to find it.