MTL - The Fallen Merman - ~ Once Upon a Spellcaster: The Golden Apple

Lingyun, a fierce and savage cultivation genius takes over a dead teenager’s body. Coincidentally, they are both named Lingyun. Set in a alternate version of the 21st century, teenager Lingyun has been killed by someone with a grudge.

- Description from Novelupdates

This novel is also known as Long Live the Mad Wife!

Daughter of the Feng Family, born a waste. Forced to marry a fool in an attempt to expel evil influences. When the first killer from the 21st century possessed this body, the sky and the earth surged. She was indifferent and cold-hearted but she let her guard down around him alone. She thought he was a pleasant sheep but didn’t expect him to be a gray wolf in disguise!

- Description from Novelupdates

A bolt of lightning descends from the sky, marking the arrival of a sweet and charming automaton girl in the Marvel universe!She’s adorable, formidable in combat, and capable of even more surprises—uh, ahem!The Marvel Cinematic Universe is rife with danger, but the life of a superhero dedicated to world peace is definitely worth looking forward to!“Waaah! Don’t pull my ears! Let me finish this game! I’ll pay, I’ll pay, okay?!”Although determined to become a superhero, games still need playing, and anime must still be watched!What? You think she’s neglecting her duties?Oh, but she possesses the incredible ability to convert concepts from various works into her own skills!For Kagura Hitomi, who wields the limitless “Conceptual Skill System,” ACG (Anime, Comics, and Games) is her ultimate source of power!