User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-3965848-20150524093458/@comment-24421137-20150524234449

@anon

Sorry anon that is incest, according to law, as that is an Affinity relationship. Affinity means you have relations with someone from your spouses bloodline. For example Issei marries Kunou, when she is 18, that means that lawfully Yasaka is like his mother, aka being related through legal mean, aka an affinity relationship. The law recognizes that if you marry someone, and then have relations with someone of that person bloodline like the mother, that is committing incest. So legaly speaking yes that would be incest.

Your relative thought would be incest by consanguinity, which means having relations with that of the same blood line, but do note that there are two different types of incest that have been recognized by the courts.

Also the way you explained makes it even weirder to me than when this conversation started.