Yandere Dark Elf: She Chased Me All the Way from Another World!

Hinata did it. He got reincarnated into another world, took up the role of Hero, and killed the dreaded Demon Lord with his party of fellow adventurers. As a reward, he's back on Earth living a normal life. Or he would be, if his dark elf companion Mariabelle hadn't decided to come to Earth and live with him. Now she uses her magic to drive off any potential romantic rivals and win Hinata's affection.