User blog comment:B214/Light Novel Volume 16 spoilers/@comment-162.202.198.72-20131019091326

The deal of LeFay becoming Issei's magician was a no-brainer if you look at it because if I was a betting man you could have bet the house on this because first thing she is extremely talented, and second she likes Issei a great deal, and wants to be with him, and Issei trust her completely, and the girl is a fan of his anyway, and third she is very cute and attractive, which Issei appreciates a great deal because he likes his eye candy, and to him it doesn't matter whether she is a human, and a young one at that because to perverts like him there is no age discrimicration in his policy.