User blog comment:Piyush Banerjee/Shin DxD 2 discussion/@comment-37165251-20181219151825/@comment-37165251-20181219155036

na @Grandpiece....it is possible (even before law) to marry a relative if he is not more near than third degree I think

Verrine is direct descendant...Vali is 3 steps more away...so it fits..

And Man they are DEVILS and not bound to beliefs and law from us Mortals ;) ^^