I slayed an Ice dragon and now I'm King of the dragon slayers - Chapter 33: The Crimson Dragon hunters sword

I, Hyoudou Issei, am a 2nd Year High school student and my age is equal to the number of years I haven’t had a girlfriend. And, someone like me got a girlfriend! I’m sorry buddies, I will walk the path of becoming an adult before you guys! – That’s how it was supposed to be, but why did I get killed by my girlfriend!? I still haven’t done anything yet! Are there no Gods in this World!? And, the person who saved me is the most beautiful girl in my school, Rias Gremory-senpai. I learned the shocking truth from her who isn’t a God but a Devil. “You have reincarnated as a Devil! Work for me!” Lured by Senpai’s breasts and treats, my life as a reincarnated Devil began. So the “Academy×Love Comedy×Battle Fantasy” starts here with just aggressive and worldly desires!

Demons, devils, ghosts and monsters

Plunge the mortals weak in horrors;

Arms of gods and blades of devils,

Shroud the world in untold evils.

Lu Sheng was an ordinary civil servant in the modern world. After waking from a drunken stupor one day, he found himself trapped in a dangerous world where demons, ghosts and supernatural monsters terrorize the land.

In this world, ordinary mortals live in dark fear and helplessness, without any means to fight against the supernatural.

As Lu Sheng struggles desperately for survival, he stumbles upon a game mod he had designed for a mobile phone app in his previous life. It unexpectedly becomes his special ability, which enables him to instantly level up any skill he learns, albeit at a cost.

Thus, Lu Sheng begins his journey, striving for power beyond the reach of a mortal as he treads the way of the Devil…

- Description from Novelupdates

I originally thought this was a world like an ordinary urban novel…Drawing comics by myself, traveling is pretty good.
But tell me, what happened to this magician called “Emiya Kiritsugu” who jumped on my face?
Who changed the settings?
Currently involved in the content of “F/Z”, “F/SN”, “Fantasy Carnival”, “The Emiya’s Meal”, “The Holy Grail of the Imperial Capital”, “FLA”, “Elmello II Event Book”, “FGO”, “FE”, etc.
Others related to “JOJO’s Bizarre Adventure”, “Rebellious Lelouch”, “Persona 5”, “Attack on Giant”, “Death”
“FGO”, “FE Series”, “FA”, “FSF”, “Cangyin”, “Magical Girl Illya” will be involved next…

- Description from novelbuddy

What if Magic has always existed ever since the beginning of the Earth we are living on, but history has been written in order to hide these facts. What if the prosperous and well-known people in history is actually a mage?

Enter a magic academy, rule your country. Be at the pinnacle of life! Join me in the journey of Emery and the others in the world of Knights and Magic as he becomes the Earth's Greatest Magus.