Tensei Shitara Slime Datta Ken (WN) - Chapter 404

A very ordinary white collar worker, Han Sang Hoon.One day, he came late to work and there he finds a strange destiny called [12 Hours After]

Follow Chen Ming as he accepts disciples, establishes a sect, and fights his way in a world that deems him a cannon fodder.
He goes against any common sense using his wits and novel knowhow to finish missions and arm himself against his cruel fate.

- Description from Novelupdates

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.

After Stargaze Family executed his family, Noel Ardagan embarked on his journey, restoring his family name with the help of a System.

"What? How the heck did she get it before me? The system told me that I'm the only one who knows about it!" Noel Ardagan cursed in anger, "That conniving murdering woman!"

"At this point in time, only I should be aware about this tomb. But how did he find out about it?" Anna Stargaze, even after her reincarnation, couldn’t comprehend Noel's actions.

The clash between of a person holding a system and a reincarnator who knows everything in the future is about to start.