MTL - Game Design: It is Very Simple For You To Fill In? - Chapter 72 you can get the answer too

It was a dangerous era. Extraterritorial ferocious beasts occupied 90% of the living space in the world, while humans could only survive in a small space. Fortunately, some of the surviving humans awakened to genetic martial arts! Breaking the shackles of one’s genetics was the foundation of cultivating martial arts. Lin Feng, who was born with congenital disease, could not experience a breakthrough. However, by some fateful encounter, he awakened to the ability to merge genes.

300 years after becoming a Demon King, the war angel Ansel faced a serious problem during a certain expedition.

——His halo grew out once again.

Ansel picked an auspicious place that was definitely and absolutely unmanned, and while cursing, he simply and skillfully broke off the newly emerged angelic aperture.

This thing was growing out faster and faster!

When will his undercover mission end already?!

The demon realm was divided and ruled by three kings. Demon King Saros was forced to go on an expedition with his sworn enemy, Ansel.

One day, he noticed Ansel sneaking away from everyone.

Saros decisively followed him, and was shocked to find that his sworn enemy, another demon king of the demon realm, took off a horn headband and fake bat wings. As Ansel cursed up and down, Saros watched as he skillfully removed a cute halo from his head.

This irritable, easily angered guy who loves fighting; the type that was cute when he shuts up but could make even demons angered to the point of ascending to heaven the moment he opens his mouth…

..was actually an angel???

- Description from Novelupdates

The protagonist fell asleep while playing an online game. However, he awoke in a strange world with his game character’s appearance. In a state of shock, he noticed that he was equipped with nothing but his strongest weapon and armor. To make matters worse, our hero’s appearance was changed by the special avatar skin『Skeleton』when he entered this new world. The protagonist wanted to live without drawing attention, but he got acquainted with the dark elf Ariana and received her request.

Amid the silence of the aftermath, a sealed envelope was found resting beside the fallen Infinity Blade. Its edges were worn, as though it had been carried for many years, yet the seal remained intact. Gok, known for his stoicism and strength, had written it long before the final battle, anticipating that one day his journey would reach its end.