MTL - Lord of Mysteries 2: Circle of Inevitability - Chapter 30 lent begins

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

"Locke transmigrated into an era where everyone had Battle Beasts. Daemons were rampant and humans were forced to build walls around their dwellings while depending on Beastmasters to keep those monsters at bay.

After being summoned in this other dimension world, all of the people that were summoned had their classes awakened. As someone that doesn’t even know English, Kim Sunhyuk had awakened as the lone Dragon Rider. But wait, there are no dragons?!?! They looked down on him, shunned him for being worse than a regular soldier, and called him a dragon-less rider. But little did they know that he would soar the skies on one above them.