This Damned Thirst for Survival - Chapter 114: (Overhaul)

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

An unnamed scout, sacrificed on the battlefield of the Southern Border, is miraculously reborn in an alternate universe. Unexpectedly, he becomes a shaman of the Orc Kingdom, even more, a rare Dragon Shaman that appears once in a millennium. What's more, he is cursed with the Blood Sacrifice of the vilest magic pet!What lies behind this curse?A charming beauty of the Fox Tribe, a Mermaid Princess from the Abyss Kingdom, a mysterious Clam Girl from the East, a Swan Warrior maiden, who is the very embodiment of an angel, all these arrive at his side one by one.Mysterious Panda Warriors from the Eastern Panta Clan, powerful Elephant Warriors of the Orephin Clan, the invincible Whale Knights of the Banilou Tribe, from the deep sea, to the formidable warriors of Summer Palace will follow our protagonist on the stage of a grand war, carving their own path to glory.Witness how our protagonist confronts his new identity, challenges the formidable human magic and invincible legions with the heroic Orc war-song. Witness how our protagonist take on the identity of the Double Dragon Shaman to defeat the Dragon Knights, leading the Bimon warriors, whose brilliance is gradually fading, and penning a saga of zero mortality amidst the battle with foreign invaders!

Hell Ghost Wang Wannian is born again, smiling and proud!
What?
Are you a soldier, will the tank drift?
You are a master, can you give birth to dragons and tigers?
You are a superman, can you call the wind thunder?
Excuse me, I am not targeting anyone, everyone in my eyes, it is rubbish!

- Description from Uukanshu (translated)