 U-Men view the failure of a graft to take as a measure of an individual's "purity" and deservedness to be one of the Third Species.When a U-Man dies, the other members of his or her team congregate for a short ceremony and then harvest the deceased U-Man's grafted mutant organs for themselves.In doing so, they believe that the fallen U-Man (as well as the mutants whose organs they harvest) will continue to live within them, a form of genetic immortality.