She Professed Herself The Pupil Of The Wiseman (WN) - Chapter 18: Learning a Skill

Chen Rui, an otaku from earth, is reborn into a human body in another world, who falls into the legendary evil, brutal world of the devil called Mozu where humans are treated as food. He has to survive while facing horrors of the devil, violent dragons and a variety of power enemies depending on a strange super system chip and his wits. Surrounded by Devil’s beauties such as black-bellied lolita princess, cold queens, violent dragons, charming poisonous devils …

Once upon a time in a modern city, a man died and was reincarnated into a body and a new mythical world.

This world holding many secrets, and wonderous things, but he possessed something that was highly regarded in terms of importance and usability: SPEED.

Join Noah on his quest to acquire great power, meet new people; while also discovering the many mysterious features of this new world he'll eventually learn to call his home.

After choking to death on a watermelon, Rong Jiahui thought that she would enter the netherworld and be reincarnated.

But when she opened her eyes, she discovered, to her very horror, that she had returned twelve years into the past…

Looking at the beautiful and awkward “little brother” that would be conferred the title of Marshal in the future for outstanding military service, she almost let out a snort of laughter.

She firmly decided to hug the thigh of this little brother, and climb to the top of her life!

The plan was beautiful, but it had just one problem.

Why had this little brother… suddenly turned into…

A little sister…

- Description from Novelupdates

The mighty void dragons are on the brink of extinction due to a strange condition. Their bodies have suddenly started rejecting their kind.

Due to that, Arad's mother dropped his egg into a forest where he could hatch safely, leaving him with a fragment of her consciousness and informing him of the condition of their race.

From that point, his goal became clear. To save their race by either mating a lot or finding a cure for their condition.

But, sadly, nothing is ever that easy. Arad is still practically a newborn and cannot tap into the terrifying might of his race, and his rarity makes him a prime target for mages and scholars seeking to study the dying race.