FATE: My Mother is Sajyou Manaka (Patreon)

Alternative titles: 

[Antichrist in the Nasuverse], [True Savior of the Evils], [Stop Adding Daughters-in-Law!], [My Son is Satan!], [Little Red Beast Looking for Mother]

Synopsis:

"Ragna, remember, the prettier the woman, the more likely she is to deceive you."

"Don't worry, Mom. I'm into that."

"???"

...

Transmigrating into the Nasuverse and becoming Beast VI, the infamous Beast from the Book of Revelation, Ragna once thought that as long as he avoided work and indulged in alcohol and women, he could surely avoid the outcome of becoming a true and complete Beast.

However, things eventually exceeded his imagination.

One by one, the women around him were tainted into Alters.