Legacy-1 and Legacy-2 searched for a target organism's "X-factor", the sequence of mutant genes that gave a mutant their superpowers. If it did not find an activated X-factor in the target, the viroid would die off, leaving the person completely unaffected. If, however, it did detect the X-factor, it would begin inserting introns (junk DNA sequences) into the transcription codings of the victim's mutant RNA, the process commonly being triggered after the patient used their powers for the first time after contracting the disease. The result was a major compromise of the replication and transcription process so disruptive as to eventually render the body incapable of creating healthy cells, ultimately resulting in the death of the victim. Prior to death, the viroid causes its host's powers to flare out of control.