User blog comment:DBard/Issei's Magician Contract/@comment-33447191-20130131040806/@comment-24098614-20131102204903

LeFay can be used by Issei because Vali was pardoned of his crimes because Odin adopted him as his son so LeFay becomes a worthy candidate, and Issei agreed to take her after her brother told Issei to accept her without question, and Issei agreed to it.