Cartwright syndrome
A certain person who causes everyone he/she fells in love with to die, is suffering from Cartwright syndrome. The term originates from the popular show Bonanza, which was about the life of the Cartwright family. Every time the character "Pa" (dad) from the show fell in love with someone, it meant that the person will die in that episode.
"-Man that girl suffers from a Cartwright syndrome. So far, every men who fell in love with her died pretty soon."