Cold-blooded Undercover Master - Chapter 13 Backing Up

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.

Our straight (?) bottom woke up ten years into the future and found himself on the bed of his childhood friend… At the start, the bottom was shocked to his very bones, but he soon quickly accepted this premise and found the whole situation to be rather amusing. Precisely then, the bottom once again went back to his timeline — back to when he and the top were just platonic childhood friends.

Landmines include but are not limited to: Sweet & naive bottom, a president story, logic is dead, slow-progressing romance, the protagonist’s name has too many character strokes, the names are hard to pronounce, too many gay characters…

- Description from novelupdates

Kamishiro Homura is a hero who once by himself exterminated the another world invader that destroyed the military all over the world. However his extreme strength made the influential people ostracized and exiled him from the society with false accusation of [Traitor] attached to him. A few years after that, for an unspecified reason Homura entered the magician academy and he looked after the girls that were ridiculed as the [burden platoon]…!? This is the raise of the curtain of a fantasy tale of the unrivaled and invincible young man where not a single ally or enemy can keep up with him, the young man who sooner or later will be extolled as the messiah by the whole human race!

After the hard struggle of a post-80s Shen Feiyang, he met with a tragic car accident in his fifties. When he again opened his eyes, he did not see the white walls of a hospital, nor had he arrived at the netherworld. Instead, he had transmigrated into the body of the post-50s young girl, Shen Yunfang.He had transmigrated into an era where people could not get enough to eat or sufficient clothes to wear.Humph, such hardships could not defeat a wise woman who had battled through society for half her life. Watch as she, with a chicken in her left hand and a duck in her right, carries a chubby baby on her back and sings triumphantly along the way.