My Power is Upgrading Everything (Rewrite) - Chapter 335: Blue-Eyed Demon Tiger King

Killing a person in ten steps will never stop a thousand miles away!

The evil leader broke through the barrier of time and space and became a descendant of Chinese medicine.

An era in which traditional Chinese medicine is in decline and ineffective.

Medicine is declining

Budo is fading

humanity is sinking

Under the surface of the peaceful world of singing and dancing, there is another treacherous and unfathomable world.

Experts can cure diseases, and national players can save people’s hearts.

- Description from novelbuddy

A 29 year old civil employment exam student wakes up in a blank white room and meets a baby angel. This baby angel informs him that he died in his sleep due to heart disease like his father and grandfather. Remembering his mom and their last conversation he says that he will take on a series of life and death tests that the baby angel offers him. From this point on he must put his life on the line and fight in the stage called ‘Arena’. And Every time he clears a test he will gain abilities and weapons to increase his strength. All to clear the tests and get his life back. This is his story of his fights in the ‘Arena’.

Roy’s life was nothing special. The only thing commendable was the last few moments when he saved a mother and her child from a drunk driver.
…
It’s really an egg! Damn it, what kind of monster have I become? Did I fall into Hell instead of making it to Heaven??
Join Roy as he ventures through various worlds with the Custom Made Demon King System—a system that allows Roy to draw anything he can imagine and create it through exchanging souls!

I finally managed to kill the demon lord.