Supervillain Idol System: My Sidekick Is A Yandere - Chapter 78 - : A Little Snack (Part 1)

Ten years ago, the Abyss invaded, and the Beast Taming Era arrived.Mo Qingchen, a transmigrant from another world, possesses a special system that not only lets him see information about beasts but also grants him the strength to fight them on his own.[Exotic Beast Name: Mouse Monster Egg; Status: Dead][Exotic Beast Name: Bronze Snake Egg; Status: Dead][Exotic Beast Name: Garlic Turtle Egg; Status: Dead]This shop just wants to rip me off.

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.

Chen Yan travels between worlds, ending up becoming an honorable prince in a medieval fantasy world. Yet this world was not quite as simple as he thought. Witches with magical powers abound, and fearsome wars between churches and kingdoms rage throughout the land.

Roland, a prince regarded as hopeless by his own father and assigned to the worst fief, spends his time developing a poor and backward town into a strong and modern city, while fighting against his siblings for the throne and absolute control over the kingdom. Join Roland as he befriends and allies with witches and, through fighting and even farming, pushes back invaders coming from the realm of evil.

- Description from Novelupdates