User blog comment:B214/High School DxD EX/@comment-201.239.133.207-20170104020556/@comment-30924344-20170209180645

Issei's children are half-bloods or triple or quadriple hybrids.

Airi=Dragon-Devil-Human

Shin=Dragon-Angel-Human

Kuernai=Dragon-Devil-Fallen Angel-Human

Shirayuki=Dragon-Devil-Nekoshou

Kurobara=Dragon-Devil-Nekoshou

Helmwidge=Dragon-Devil-Half God

Ex=Dragon-Devil

Robertina=Dragon-Devil

Zen=Dragon-Devil-Human

Ernestein=Dragon-Vampire

Unnamed Pendragon=Dragon-Human

Now if Issei has children with Bennia and Kunou which no doubtely he will because the obvious is so obvious, then they would look like this:

Unnamed [Kunous child will have a singular name as she doesn't have a surname]=Dragon-Kitsune

Unnamed [same for Bennia's child ^]=Dragon-Devil-Grim Reaper-Human