User blog comment:B214/Question and Answers 6/@comment-190.164.227.239-20161201033222/@comment-207.96.205.3-20161214052719

Do not forget that in Volume 21 or 22, one of the two, that someone said that Issei and Vali are the two strongest possessor of their respective sacred gear. Vali by his birth and talent. Issei shares his talent, he has become so strong in less than a year. They are BOTH of the prodigy