Assassin's Pride

I rmbr watching the anime
Why is there only 48 chapters

"The sun, moon and stars have long disappeared from the sky, leaving the world in eternal darkness. The remains of humanity live inside Flandore, the last city-state, while monstrous beings roam free in the endless night outside. However, humanity has gained a power called Mana that allows them to fight those monsters, and those who hold that power form the aristocracy that rules over the common people in Flandore.

Among those aristocrats, a girl is born without any talent to use Mana. A youth named Kufa is dispatched as a tutor to find if Melida Angel has any Mana inside her. If she is not talented, he must assassinate her. However, Kufa is inspired by Melida's determination and decides to do everything in his power to ensure that the day where he kills her never arrives."

(There's a novel.)

https://www.mangaupdates.com/series/t0jsea0/assassin-s-pride

Can someone explain to me the only thing the villains do is find out if the useless Melinda is the daughter of the biological daughter of her noble father or the supposed lover of his wife, who have nothing better to do than conquer the world

I want more of this