Lilith: Origin of Succubi - Chapter 16

In a world where magic is forbidden and witches are hunted, Ashlynn Blackwell has hidden her mark of the witch since birth. The night of her wedding she's betrayed and her secret is exposed. Attacked by her husband and his knights, Ashlynn was abandoned and left for dead in the wilderness.Rescued by the vampire lady Nyrielle, Ashlynn is offered a choice: die as a human or embrace her power as a witch. Bound by a mystical blood pact, Ashlynn is plunged into a world of ancient magic, immortal vampires, and deadly political intrigue for the chance to find eternal love.

A chance to change, to challenge destiny, making dreams a reality, and live a legend! A regular man gains a system that allows him to turn into a fish!

- Description from Novelupdates

Chiyuki Hoshino, a beautiful otaku girl, traveled to the world of Yu-Gi-Oh! with her Fate/Grand Order Heroic Spirit deck.“Blue-Eyes White Dragon!”“Activate the effect of Arash! Stella!”“My most loyal servant, the Dark Magician!”“Activate the effect of Arash! Stella!”“I…”“Activate the effect of Arash! Stella!!!”Amid the ruins and countless corpses (thanks to Arash), Chiyuki wiped her forehead and smiled brightly. “Playing cards is so damn interesting.”For those interested in reading this fanfic, please note that I am not the original author. I have only translated and edited it to make it as readable as possible.

Struck down amid the battle, the Hero and Demon King meet their demise. As their souls linger on the edge of the afterlife, a mysterious force intervenes, merging their fragmented souls together with a new being. Rusty, the living armor, now affected by their memories and presence, embarks on his own quest. Will he seek revenge on those who betrayed the hero, or will he fulfill the desires of the fallen demon king? or instead, forge his own path?