House of Hidden Identities

I am the Holy Maiden of the Spirit Realm, and my son is the next Holy Son. But my husband and daughter are both mortals. To hide our identities, my son and I spend our days at home playing the part of a perfectly ordinary family. Then, at night, once the father and daughter are asleep, we change at lightning speed and return to the Spirit Realm to handle government affairs. I thought we could keep living like this forever. But then the Demon Realm suddenly launched a war. To protect that delicate father-daughter pair, we had no choice but to stage our deaths through tears and head for the battlefield. But… can someone please tell me why the black-clad god of slaughter across from me, the one carrying two massive battle-axes, looks exactly like my sickly husband who can barely take three steps without swaying? And why does that little she-devil charging in and out of the enemy ranks, killing everything in sight while cackling like mad, look so much like my gentle, sweet, beautiful, and well-behaved little daughter?