Apocalypse: Zombie King is the Female Lead's Younger Sister - Chapter 8: Fox Form

One-eyed Wolf Lecan is a skilled adventurer who has conquered many dungeons all over the world. He had been going solo for a long time, but in the last three years, he’s had a partner. That partner jumps into the black hole together with Lecan, and both go their separate ways as they fall into another world. Dungeons and magical beasts also exist in that world. After learning the native language, Lecan goes on a journey. Meeting a good teacher, Lecan studies medicine making and magic under that teacher, and begins his dungeon explorations for real.

What the hell? That menace who bullied me since I was six years old, actually became a pretty girl after three years of living apart? And she even ran to our agreed duel location to confess to me, hoping that I can become her boyfriend?!

This is a plot against me! There’s definitely an enormous conspiracy behind this! I won’t be fooled by you! Even if you tear up and act all pitiful, I will still disregard you and humiliate you, until you’ve have completely paid back all my childhood grievances!

What’cha lookin’at? There are very reasonable grounds for bullying a girl!

- Description from Novelupdates

Tian Han was a young boy who admired immortals. His dream had always been to become like them—flying on swords, using spells. But he was just an ordinary village boy, and he didn't have much of a chance for that. So, he always read books about immortals, and his admiration for them grew more and more every day. One day, he heard that he had a chance to become an immortal.“You can become immortal.”This was the sentence where his adventure began. Yes, he could become an immortal. And so, his journey started, and he found himself in the ruthless world of immortals.

Suddenly a high school student Subaru Natsuki has been summoned to another world on the way back from the convenience store. With the biggest crisis of his life being summoned to another world and no sign of the one who summoned him things become worse when he is attacked.