MTL - Since 2000 - ~ 2 books recommended

Coming from the modern era, she was sent to a strange world. The body she possessed previously belonged to a young woman whose family was thrown away by their clan. However with the “Dan Fu Zong”, the inheritance from her old world, she steps on the path of cultivation, hoping to one day become an immortal.

- Description from Novelupdates

In a world where beast masters rule by taming magical creatures and competing in thrilling tournaments, becoming the most celebrated sport, Eratz seemed destined for greatness. Surrounded by friends and family, his path was set until a shocking betrayal shattered his dreams.Fueled by the pain of his betrayal, Eratz looks up at the night sky, finding a new purpose. He vows to rise from the ashes and conquer the beast master world, determined to become the greatest and reclaim his lost honor.

A story in which a woman, after learning that the world would end in ten days, sets out to finish one last thing: murder her ex-girlfriend.

However, she ends up befriending, and spending the world’s final days with, the little sister of her ex-girlfriend instead.

Being given a chance and reincarnated is nice and all, yet why do I have to become that male friend who just watches the protagonist flirting with his harem?---World: Kaguya-sama: Love Is War - Hyouka ----