User blog comment:B214/Question and Answers 4/@comment-24331706-20150319150433/@comment-25032153-20150320140800

well the reincarnated devils get bodies like the pure-bloo devils as they get all the weaknesses like light form angels. SO they get the aging abilities so they can hold an age similar to their daughter inthe gremory clan were Rais's mother looked the same age as her. Also if you look at after Issei's age was only be agle to go to 1000 after juggernaut drive cut his live down that is what made it closed to him. SO after issei got a dragon body his life was also going infifte and dreams which is 0 and infinty as his life is unstable we dont know how long he will live but we know that he will live longer than his home friends.