The First Demon King: I Became a Demon to Resurrect My Wife

I was once the strongest hero in the world. I slew dragons, killed gods, and basked in boundless glory.

Now I am the strongest Demon King in the world. I have waged war for a thousand years and crossed countless cycles of reincarnation, all to bring my beloved elf princess back to life.

When the newcomer hero arrived with his System and shattered my last hope with a single punch,

he thought he was facing a fiend bent on destroying the world.

No. What he awakened was the madness of a husband who would cross the divide between life and death to find his wife again...