The crimson princess - Chapter 59 - 15 years old

Ayaan is a young resident aspiring to be a surgeon, the final stage of a full on graduated plague doctor. However, in her attempt to redeem herself after a sudden discontinuation, she finds herself unravelling mysteries about her institution that are rather gut wrenching. Stick around and watch her persevere in a world full of monsters; creatures and humans alike.

In a parallel world filled with pet beasts, people tame, train, evolve, and trade beasts.

In the King’s game, the [King]’s order is absolute and has the power to create rules. As the owner of a special physique, Gu Huai was selected by the system to participate in the game. “Win the game and become the [King], and you can obtain whatever it is you desire.”

- Description from Novelupdates

…but it seems pretty doable.