The Temptation of the Sea?

Yandere Dark Elf: She Chased Me All the Way From Another World! · Episode 11 · “The Temptation of the Sea?”

Hinata did it. He got reincarnated into another world, took up the mantle of Hero, and slew the dreaded Demon Lord alongside his party of fellow adventurers. As his reward, he’s returned to Earth to resume a normal life. Or it would be if it wasn’t for the fact that his dark elf companion...