Demona and Macbeth's Link

Demona and Macbeth were linked by a spell that the Weird Sisters placed upon them in 1040 A.D.

They became immortal and unable to age. When they are in close proximity with each other, they will feel the other's pain, and to a lesser extent, pleasure. The only they can die is to be killed by the other. If either one is killed by someone else, they will return to life.

Across the mists of space and time,
we pose this covenant sublime.
Macbeth his youth doth offer here,
to make this one a force to fear.
While she with fang and claw and wing
doth swear sweet death his foes to bring.
By their acceptance are they consigned
unto each other's fate designed,
forever and eternal bound,
and each the other's pain resound.