University Doctor and His Fragile Patients - Chapter 23: Classmate, That’s Not Period Pain—It’s Appendicitis

Violet skies, a world undergoing massive changes, a deficient moon, interlinking voids…
When the world experienced a cataclysmic event,the majority of living things ceased to exist. Although humanity survived by hiding in the last safe zones, humans had to face mutated dire beasts and colossal source beasts that could break through the space barrier and enter the earth at any second.
Luo Yunyang, a young man who grew up in those calamitous times, obtained an attribute regulator and set out to walk the path of supremacy!

- Description from novelupdates

Ethan transmigrated from earth to a post apocalyptic martial world with a system.His system has only one function: Double the attribute every day. Watch him rising in the universe with a pace faster than the speed of light.

Yeon-woo had a twin brother who disappeared five years ago. One day, a pocket watch left by his brother returned to his possession. Inside, he found a hidden diary in which was recorded “By the time you hear this, I guess I will be already dead….”