User blog comment:B214/Talk About What You Want! 2/@comment-4547267-20140720054308/@comment-1359322-20140725063226

What do you mean they left, Kuroka and Le Fay are still part of the Vali Team, they are more active with that group rather than with Issei and his companions. Kuroka and Le Fay are just staying in the Hyoudou Residence, if Vali needs them, they'll still straight go to Vali rather than Issei.