Also called the body sympathy spell, this spell puts the wizard and a target creature in a two-way sympathetic link. Any damage inflicted on the mage is automatically inflicted on the linked creature as well; should the caster die, so too will the linked creature. Conversely, if the linked creature is damaged or hurt, the caster will be hurt as well.
Saving throws, ability checks, and Armor Class are considered those of the individual attacked—only the effect is carried over to the partner in the death link. The only exception is that if the linked creature dies, the caster survives unless enough hit points of damage have been received through the link to prove fatal. Both curative and destructive spells cross the link—healing one party heals the other.
Once cast, the spell cannot be ended by either party until its duration runs out or one or the other party physically leaves the plane of existence the other occupies. Distance between the parties (except at the initial casting) has no effect on this spell.
The death link is occasionally used as a tool of revenge by powerful mages against individuals weaker than themselves, but it is more often used as a vouchsafe to protect one side or the other in negotiations—if both sides can be hurt by a single act of treachery, then both sides tend to negotiate in better faith.