This Earth Is A Bit Fearsome - Chapter 44

However, he did not know that he was not raising just a harmless pet, but a biological weapon secretly made by the government… a real monster.

As a former librarian, Rand felt that he had been living an ordinary life, the one that he had reclaimed unconsciously every single day.

Recently, he has been a little upset because the pet fish he accidently brought home to raised seems to have undergo some strange changes

Well, it turned into a merman.

- Description from Novelupdates

Mu Yue traveled to the world of Naruto and became an ordinary chuunin teacher at Konoha Ninja School and a member of the Root Organization.

Fortunately, after awakening the teacher system, you can become stronger by teaching.

In order not to become Danzo’s consumables, Mu Yue worked hard to teach and increase her strength.

“Complete the teaching rated A for the first time and receive the reward – mastery of fire attribute chakra properties change.”

“Under your guidance, Uchiha Shisui has worked hard to practice, and his overall strength has been greatly improved, and he has been rewarded – the Immortal Human Body!”

Under Mu Yue’s guidance, Zhishui understood that the village’s enemies were not necessarily other big countries, but could also be within the village. People who spoke righteously about the will of fire might not necessarily act in accordance with the will of fire.

Obito got rid of the title of being the weakest person in the ninja school, and Metkai became a master of physical skills even earlier…

- Description from novelbuddy

Lin Wu was a university student that died after having one too many energy drinks and then reincarnated into the body of a worm. He awakens to find out that he now has a system, but even it doesn't have a clear idea of where they are.

He comes out of the ground and discoverers that he’s no longer in his previous world but rather in a cultivation world.

Witness Lin Wu’s journey as he worms his way to the heavens from a tiny worm crawling in the ground.