Tyranny of Steel - Chapter 104: Call to Arms!

All I ever wanted was for famous detectives like Sherlock Holmes or Arsène Lupin to appear in my dreams and share their wisdom. But instead, why am I hearing the voices of notorious serial killers in my head, guiding me to solve a string of mysterious cases?

Due to being reincarnated into a financially struggling noble family, I had to find a way to make money.“Just wait one more day, and the next volume will be out!”“Next week is a hiatus? Are you out of your mind?”“Hurry up and give me the next volume!”“Quickly!”Before I knew it, I was overwhelmed with deadlines instead of romance.

A supreme expert in the Immortal World had died, and a strand of his soul returned to its original body on Earth. Tang Xiu discovered with amazement that ten thousand years passed in the Immortal World, yet only a single year passed on Earth.

Ruthlessly betrayed by his lover and trusted friends, Tang Xiu found that his soul went back to his previous body on Earth, and, despite he spent 10,000 years in the Immortal World, just a year has passed on Earth and many things have changed. Having an unsurpassed knowledge, Tang Xiu will protect his loved ones and go back to the Immortal World to take his revenge.

- Description from Novelupdates

I finally managed to kill the demon lord.